simplemvvmtoolkit Wiki Rss Feed

Updated Wiki: Prerequisites

tonysneed — Thu, 28 Feb 2013 13:28:52 GMT

Prerequisites for v.3 for VS 2010

1. Visual Studio 2010 with Service Pack 1
Professional or Higher: http://www.microsoft.com/visualstudio/en-us/download
Or Express: http://www.microsoft.com/express/Download

2. Silverlight 4 Tools
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=b3deb194-ca86-4fb6-a716-b67c2604a139

3. Silverlight 5 Tools for VS 2010 SP1
http://www.microsoft.com/download/en/details.aspx?id=28358

4. Silverlight 4 Toolkit (April 2010)
http://silverlight.codeplex.com/releases/view/43528

5. Silverlight 5 Toolkit (December 2011)
http://silverlight.codeplex.com/releases/view/78435

6. Expression Blend 4 SDK (or Expression Blend 4 complete)
SL4: http://www.microsoft.com/downloads/en/details.aspx?FamilyID=d197f51a-de07-4edf-9cba-1f1b4a22110d&displaylang=en
WPF: http://www.microsoft.com/downloads/en/details.aspx?FamilyID=75E13D71-7C53-4382-9592-6C07C6A00207

7. Expression Blend Preview for Silverlight 5
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=22feb67c-4f65-4ced-97cf-5f8ada296445&displaylang=en

8. Windows Phone SDK 7.1
http://www.microsoft.com/download/en/details.aspx?id=27570
If installing on Windows 8, see this post.

9. .NET Framework 4.5 (required for installer)
http://www.microsoft.com/en-us/download/details.aspx?id=30653

10. For Samples: SQL Server 2008 Express (database with management tools)
http://www.microsoft.com/express/Database/InstallOptions.aspx

11. For Samples: Northwind Sample Database
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=06616212-0356-46a0-8da2-eebc53a68034&displaylang=en
- Make sure to attach the Northwind database to the SQLExpress instance

Updated Wiki: Prerequisites

tonysneed — Thu, 28 Feb 2013 12:27:24 GMT

Prerequisites for v.3 for VS 2010

1. Visual Studio 2010 with Service Pack 1
Professional or Higher: http://www.microsoft.com/visualstudio/en-us/download
Or Express: http://www.microsoft.com/express/Download

2. Silverlight 4 Tools
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=b3deb194-ca86-4fb6-a716-b67c2604a139

3. Silverlight 5 Tools for VS 2010 SP1
http://www.microsoft.com/download/en/details.aspx?id=28358

4. Silverlight 4 Toolkit (April 2010)
http://silverlight.codeplex.com/releases/view/43528

5. Silverlight 5 Toolkit (December 2011)
http://silverlight.codeplex.com/releases/view/78435

7. Expression Blend Preview for Silverlight 5
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=22feb67c-4f65-4ced-97cf-5f8ada296445&displaylang=en

8. Windows Phone SDK 7.1
http://www.microsoft.com/download/en/details.aspx?id=27570
If installing on Windows 8, see this post.

9. WCF RIA Services V1.0 SP1 for Silverlight 4
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=330F6831-5B90-4315-B042-96127A4A7EFC&displaylang=en

10. For Samples: SQL Server 2008 Express (database with management tools)
http://www.microsoft.com/express/Database/InstallOptions.aspx

Updated Wiki: Prerequisites

tonysneed — Thu, 28 Feb 2013 12:26:38 GMT

Prerequisites

1. Visual Studio 2010 with Service Pack 1
Professional or Higher: http://www.microsoft.com/visualstudio/en-us/download
Or Express: http://www.microsoft.com/express/Download

2. Silverlight 4 Tools
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=b3deb194-ca86-4fb6-a716-b67c2604a139

3. Silverlight 5 Tools for VS 2010 SP1
http://www.microsoft.com/download/en/details.aspx?id=28358

4. Silverlight 4 Toolkit (April 2010)
http://silverlight.codeplex.com/releases/view/43528

5. Silverlight 5 Toolkit (December 2011)
http://silverlight.codeplex.com/releases/view/78435

7. Expression Blend Preview for Silverlight 5
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=22feb67c-4f65-4ced-97cf-5f8ada296445&displaylang=en

8. Windows Phone SDK 7.1
http://www.microsoft.com/download/en/details.aspx?id=27570
If installing on Windows 8, see this post.

9. WCF RIA Services V1.0 SP1 for Silverlight 4
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=330F6831-5B90-4315-B042-96127A4A7EFC&displaylang=en

10. For Samples: SQL Server 2008 Express (database with management tools)
http://www.microsoft.com/express/Database/InstallOptions.aspx

Updated Wiki: Home

tonysneed — Thu, 08 Nov 2012 16:05:44 GMT

Project Description

Simple MVVM Toolkit makes it easier to develop Silverlight, WPF and WP7 applications using the Model-View-ViewModel design pattern. The purpose of the toolkit is to provide a simple framework and set of tools for getting up to speed quickly with applications based on the MVVM design pattern. The emphasis is on simplicity, but it contains everything you need to implement MVVM for real-world line of business applications.

What’s Hot

Simple MVVM Toolkit v4 now supports Visual Studio 2012! Use v4 to develop SL5 (including Ria Services) and WPF 4.5 apps. If you are still using Visual Studio 2010, which is required for Windows Phone 7 apps, then install Simple MVVM Toolkit v3.

All assemblies are now signed, which means you can reference them from other signed assemblies. Several bugs have been fixed in both v3.1 and v4.0. See the download details for a list of issues addressed.

Simple MVVM Toolkit v4 for Visual Studio 2012 is built using Portable Class Library tools, so that it will be easier to add support for other platforms. Support for Windows 8/WinRT, as well as Windows Phone 8, will be added in a subsequent release.

I have also updated all the NuGet packages for SimpleMvvmToolkit to version 3.1.0.0 for SL4, SL5, WP7 and WPF4 (VS 2010), and I uploaded a new NuGet package for WFP 4.5 (VS 2012). But keep in mind these NuGet packages only contain the DLLs -- to get the code snippets and item and project templates, you only need to download and run the installer.

Take a look at the Getting Started screencast!

You can watch it now or download the screencast to watch it offline on your pc or mobile device.

View the Real-World MVVM with RIA Services Screencast:
Real-World MVVM Part 1: Streaming or Download (PC or mobile device)
Real-World MVVM Part 2: Streaming or Download (PC or mobile device)

Simple MVVM Toolkit can be downloaded from within Visual Studio by selecting the Tools menu, Extension Manager!

Simple MVVM Toolkit now has an installer! Just download and run it.

Simple MVVM Toolkit has some awesome Visual Studio project templates!

From within Visual Studio, select File, New Project, then click on the Mvvm category under either Windows (for WPF), Silverlight, or Silverlight for Windows Phone. After clicking OK you get a complete project with a folder structure and a ready-made MVVM app.

Here is what you get from the Silverlight project template. Just follow the instructions in ReadMe.txt.

Here is what you get from the RiaServices template. Just hit F5 and you’ll see a fully functional MVVM Silverlight app that uses WCF RIA Services.

The kicker is that you also get a Test project that uses the Microsoft Silverlight Testing Framework.

Features

New Features in v2:

An Installer that places the binaries, templates and snippets in all the right places.
- Copies binaries, libraries, samples and source code to one location
- Copies Visual Studio templates and code snippets to the correction location
- Registers the binaries so that SimpleMvvmToolkit appears in the Visual Studio Add References dialog.
Visual Studio project templates
- Project templates for Silverlight, Windows Phone and WPF, which include starter Locator, Model, ViewModel, View and ServiceAgent classes.
- A multi-project Visual Studio template that includes a Silverlight client, a Silverlight Unit Test project and a WCF RIA Services project.
The main sample now has Parts 2 and 3
- Part 2 demonstrates navigation, messaging, property associations, async
- Part 3 demonstrates using the toolkit with WCF RIA Services, including persistence with CRUD operations
Simplified and consolidated ViewModelLocator template which creates ViewModels on-demand.
- This allows Views to control the ViewModel lifetime, avoiding potential memory leaks
- Silverlight and Windows Phone apps use the same ViewModelLocator template
- The code snippet to insert injected (for dependency injection using MEF) ViewModels is more robust
Improved support for unit testing (with the Silverlight Unit Testing Framework – included in the Silverlight Toolkit)
- Includes an extension method for enqueuing conditional tasks with a timeout
Simpler and more robust MessageBus
- Now uses leak-proof eventing model so that unregistering for messages is no longer required
- ViewModelBase now includes helper methods for sending and receiving messages
GenericDelegateCommand supports parsing string parameters from XAML
- Plays nicer with CommandParameter in XAML

Other Features:

Support for Silverlight, WPF and Windows Phone 7
Helper classes, Visual Studio templates, code snippets
- Helpers: Model and view-model base classes, MessageBus,
  DelegateCommand, MEF Export attribute
- Templates: View-model, detail view-model,
  view-model locator, injected view-model locator
- C# Code Snippets: bindable property, vm locator, command
- XML Code Snippets: Blend event-trigger
Sample applications with step-by-step instructions
- End-to-end Silverlight Mvvm sample using WCF
- Simplified “Getting Started” sample
- Associated properties sample
- Async execution sample
- Enum to list conversion sample
- Message bus sample
- Navigation sample
- Dependency injection (MEF) with unit testing
Model and ViewModel base classes
Strongly typed data binding with lambda expressions
View-model locator service
DelegateCommand based on ICommand
AssociateProperties method to link view-model and model properties
Event-based facility for two-way communication between views and view-models
MessageBus for sending notifications in a loosely coupled fashion among view-models
Dependency injection (IoC) for unit testing using MEF (Managed Extensibility Framework)
IEditableDataObject support with deep cloning
Conversion of enums to lists for populating combo boxes
Async support with transparent marshaling to the UI thread
Built-in support for WCF RIA Services

What You Get

The toolkit consists of a set of helper classes, some Visual Studio templates, and a set of code snippets. All you have to do is reference the helper assembly (or include the Visual Studio project in your solution), add view-models using the Visual Studio item templates, and insert properties using the included mvvmprop code snippet. The view-models extend a base class that supplies two-way data binding. There is also an item template for a detail-based view model that extends a base class with editing capability (via IEditableDataObject). You can also add a view-model locator using the corresponding item template and code snippet.

Getting Started

The best way to get started is to open the Getting Started sample in Samples\SimpleMvvm-Other and follow instructions in the Getting Started section of the online Documentation for creating a Silverlight MVVM application from scratch using the toolkit.

After creating your first app, you’re ready to explore the main sample app. Open up Before and After versions of the sample application included in the downloaded zip file. There is a ReadMe.txt file with detailed step-by-step instructions. The Before solution is an n-tier application that retrieves products and categories from the Northwind sample database using a basic WCF service. (In case you'd like to reproduce the Before project, there is a text file describing how to do that.)

Next you can check out samples for async execution, associated properties, enum to list conversion, notifications using the Message Bus, using view-model driven navigation, and dependency injection with unit testing.

About the Author

Tony Sneed is an instructor for the developer training company, DevelopMentor, where he authors and teaches courses on .NET 3.5-4.0, Entity Framework, Windows Communication Foundation and Silverlight. He has a keen interest in MVVM, Managed Extensibility Framework, and WCF RIA Services. You can read his blog or follow him on Twitter and Facebook, where he has created a group for people using MVVM to design Silverlight applications. He is a frequent speaker at user groups and conferences and has written articles for MSDN Magazine.

What's Next?

I plan to put out additional blog posts and a series of screen casts on using the Simple MVVM Toolkit and exploring different features.

Updated Wiki: Home

tonysneed — Sun, 04 Nov 2012 04:08:06 GMT

Project Description

What’s Hot

Take a look at the Getting Started screencast!

You can watch it now or download the screencast to watch it offline on your pc or mobile device.

View the Real-World MVVM with RIA Services Screencast:
Real-World MVVM Part 1: Streaming or Download (PC or mobile device)
Real-World MVVM Part 2: Streaming or Download (PC or mobile device)

Simple MVVM Toolkit can be downloaded from within Visual Studio by selecting the Tools menu, Extension Manager!

Simple MVVM Toolkit now has an installer! Just download and run it.

Simple MVVM Toolkit has some awesome Visual Studio project templates!

Here is what you get from the Silverlight project template. Just follow the instructions in ReadMe.txt.

Here is what you get from the RiaServices template. Just hit F5 and you’ll see a fully functional MVVM Silverlight app that uses WCF RIA Services.

The kicker is that you also get a Test project that uses the Microsoft Silverlight Testing Framework.

Features

New Features in v2:

An Installer that places the binaries, templates and snippets in all the right places.
- Copies binaries, libraries, samples and source code to one location
- Copies Visual Studio templates and code snippets to the correction location
- Registers the binaries so that SimpleMvvmToolkit appears in the Visual Studio Add References dialog.
Visual Studio project templates
- Project templates for Silverlight, Windows Phone and WPF, which include starter Locator, Model, ViewModel, View and ServiceAgent classes.
- A multi-project Visual Studio template that includes a Silverlight client, a Silverlight Unit Test project and a WCF RIA Services project.
The main sample now has Parts 2 and 3
- Part 2 demonstrates navigation, messaging, property associations, async
- Part 3 demonstrates using the toolkit with WCF RIA Services, including persistence with CRUD operations
Simplified and consolidated ViewModelLocator template which creates ViewModels on-demand.
- This allows Views to control the ViewModel lifetime, avoiding potential memory leaks
- Silverlight and Windows Phone apps use the same ViewModelLocator template
- The code snippet to insert injected (for dependency injection using MEF) ViewModels is more robust
Improved support for unit testing (with the Silverlight Unit Testing Framework – included in the Silverlight Toolkit)
- Includes an extension method for enqueuing conditional tasks with a timeout
Simpler and more robust MessageBus
- Now uses leak-proof eventing model so that unregistering for messages is no longer required
- ViewModelBase now includes helper methods for sending and receiving messages
GenericDelegateCommand supports parsing string parameters from XAML
- Plays nicer with CommandParameter in XAML

Other Features:

Support for Silverlight, WPF and Windows Phone 7
Helper classes, Visual Studio templates, code snippets
- Helpers: Model and view-model base classes, MessageBus,
  DelegateCommand, MEF Export attribute
- Templates: View-model, detail view-model,
  view-model locator, injected view-model locator
- C# Code Snippets: bindable property, vm locator, command
- XML Code Snippets: Blend event-trigger
Sample applications with step-by-step instructions
- End-to-end Silverlight Mvvm sample using WCF
- Simplified “Getting Started” sample
- Associated properties sample
- Async execution sample
- Enum to list conversion sample
- Message bus sample
- Navigation sample
- Dependency injection (MEF) with unit testing
Model and ViewModel base classes
Strongly typed data binding with lambda expressions
View-model locator service
DelegateCommand based on ICommand
AssociateProperties method to link view-model and model properties
Event-based facility for two-way communication between views and view-models
MessageBus for sending notifications in a loosely coupled fashion among view-models
Dependency injection (IoC) for unit testing using MEF (Managed Extensibility Framework)
IEditableDataObject support with deep cloning
Conversion of enums to lists for populating combo boxes
Async support with transparent marshaling to the UI thread
Built-in support for WCF RIA Services

What You Get

Getting Started

About the Author

What's Next?

I plan to put out additional blog posts and a series of screen casts on using the Simple MVVM Toolkit and exploring different features.

Updated Wiki: Home

tonysneed — Sat, 20 Oct 2012 13:18:44 GMT

Project Description

What’s Hot

Take a look at the Getting Started screencast!

You can watch it now or download the screencast to watch it offline on your pc or mobile device.

View the Real-World MVVM with RIA Services Screencast:
Real-World MVVM Part 1: Streaming or Download (PC or mobile device)
Real-World MVVM Part 2: Streaming or Download (PC or mobile device)

Simple MVVM Toolkit can be downloaded from within Visual Studio by selecting the Tools menu, Extension Manager!

Simple MVVM Toolkit now has an installer! Just download and run it.

Simple MVVM Toolkit has some awesome Visual Studio project templates!

Here is what you get from the Silverlight project template. Just follow the instructions in ReadMe.txt.

Here is what you get from the RiaServices template. Just hit F5 and you’ll see a fully functional MVVM Silverlight app that uses WCF RIA Services.

The kicker is that you also get a Test project that uses the Microsoft Silverlight Testing Framework.

Features

New Features in v2:

An Installer that places the binaries, templates and snippets in all the right places.
- Copies binaries, libraries, samples and source code to one location
- Copies Visual Studio templates and code snippets to the correction location
- Registers the binaries so that SimpleMvvmToolkit appears in the Visual Studio Add References dialog.
Visual Studio project templates
- Project templates for Silverlight, Windows Phone and WPF, which include starter Locator, Model, ViewModel, View and ServiceAgent classes.
- A multi-project Visual Studio template that includes a Silverlight client, a Silverlight Unit Test project and a WCF RIA Services project.
The main sample now has Parts 2 and 3
- Part 2 demonstrates navigation, messaging, property associations, async
- Part 3 demonstrates using the toolkit with WCF RIA Services, including persistence with CRUD operations
Simplified and consolidated ViewModelLocator template which creates ViewModels on-demand.
- This allows Views to control the ViewModel lifetime, avoiding potential memory leaks
- Silverlight and Windows Phone apps use the same ViewModelLocator template
- The code snippet to insert injected (for dependency injection using MEF) ViewModels is more robust
Improved support for unit testing (with the Silverlight Unit Testing Framework – included in the Silverlight Toolkit)
- Includes an extension method for enqueuing conditional tasks with a timeout
Simpler and more robust MessageBus
- Now uses leak-proof eventing model so that unregistering for messages is no longer required
- ViewModelBase now includes helper methods for sending and receiving messages
GenericDelegateCommand supports parsing string parameters from XAML
- Plays nicer with CommandParameter in XAML

Other Features:

Support for Silverlight, WPF and Windows Phone 7
Helper classes, Visual Studio templates, code snippets
- Helpers: Model and view-model base classes, MessageBus,
  DelegateCommand, MEF Export attribute
- Templates: View-model, detail view-model,
  view-model locator, injected view-model locator
- C# Code Snippets: bindable property, vm locator, command
- XML Code Snippets: Blend event-trigger
Sample applications with step-by-step instructions
- End-to-end Silverlight Mvvm sample using WCF
- Simplified “Getting Started” sample
- Associated properties sample
- Async execution sample
- Enum to list conversion sample
- Message bus sample
- Navigation sample
- Dependency injection (MEF) with unit testing
Model and ViewModel base classes
Strongly typed data binding with lambda expressions
View-model locator service
DelegateCommand based on ICommand
AssociateProperties method to link view-model and model properties
Event-based facility for two-way communication between views and view-models
MessageBus for sending notifications in a loosely coupled fashion among view-models
Dependency injection (IoC) for unit testing using MEF (Managed Extensibility Framework)
IEditableDataObject support with deep cloning
Conversion of enums to lists for populating combo boxes
Async support with transparent marshaling to the UI thread
Built-in support for WCF RIA Services

What You Get

Getting Started

About the Author

What's Next?

I plan to put out additional blog posts and a series of screen casts on using the Simple MVVM Toolkit and exploring different features.

New Comment on "WCF RIA Services"

junwebhead — Sun, 13 May 2012 02:45:09 GMT

Hi Tony, I never had a chance to thank you for your awesome work. Thank you very much! To be honest, I've been struggling with MVVM for some time already until I found simplemvvmtoolkit. Other examples/videos are just to vague for me. I mean they are too simple to be a realistic reference. Your RealWorld demonstration however is very helpful together with the great documentation and active discussions. Thank you!

New Comment on "Programming Reference"

adolfo1981 — Fri, 13 Apr 2012 16:49:11 GMT

I agree, this is one of the best and most well documented MVVM frameworks I have found. Flawless installation and very complete sample applications. I decided to use it for a big WPF application I'm building and it solves most of the issues I've run into, like communication between V and VM's, and Notifications in general, now I'll try to integrate it to Unity IoC Container now that I see Tony has added Dependency Injection Support!. I've also contacted Tony with some questions and he has been very helpful and supportive. We appreciate all the efforts you've put into this Tony!

Updated Wiki: Prerequisites

tonysneed — Wed, 07 Mar 2012 20:44:27 GMT

Prerequisites

1. Visual Studio 2010 with Service Pack 1
Professional or Higher: http://www.microsoft.com/visualstudio/en-us/download
Or Express: http://www.microsoft.com/express/Download

2. Silverlight 4 Tools
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=b3deb194-ca86-4fb6-a716-b67c2604a139

3. Silverlight 5 Tools for VS 2010 SP1
http://www.microsoft.com/download/en/details.aspx?id=28358

4. Silverlight 4 Toolkit (April 2010)
http://silverlight.codeplex.com/releases/view/43528

5. Silverlight 5 Toolkit (December 2011)
http://silverlight.codeplex.com/releases/view/78435

7. Expression Blend Preview for Silverlight 5
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=22feb67c-4f65-4ced-97cf-5f8ada296445&displaylang=en

8. Windows Phone SDK 7.1
http://www.microsoft.com/download/en/details.aspx?id=27570

9. WCF RIA Services V1.0 SP1 for Silverlight 4
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=330F6831-5B90-4315-B042-96127A4A7EFC&displaylang=en

10. For Samples: SQL Server 2008 Express (database with management tools)
http://www.microsoft.com/express/Database/InstallOptions.aspx

Updated Wiki: Home

tonysneed — Fri, 02 Mar 2012 16:27:45 GMT

Project Description

What’s Hot

Simple MVVM Toolkit now supports Silverlight 5.0 and Windows Phone 7.1! Project templates for both SL4 and SL5 are included, so you can use both. Samples have also been upgraded. Get it here. Check the new list of prerequisites.

Compare Simple MVVM Toolkit to MVVM Light Toolkit.

Take a look at the Getting Started screencast!

You can watch it now or download the screencast to watch it offline on your pc or mobile device.

View the Real-World MVVM with RIA Services Screencast:
Real-World MVVM Part 1: Streaming or Download (PC or mobile device)
Real-World MVVM Part 2: Streaming or Download (PC or mobile device)

Simple MVVM Toolkit can be downloaded from within Visual Studio by selecting the Tools menu, Extension Manager!

Simple MVVM Toolkit now has an installer! Just download and run it.

Simple MVVM Toolkit has some awesome Visual Studio project templates!

Here is what you get from the Silverlight project template. Just follow the instructions in ReadMe.txt.

Here is what you get from the RiaServices template. Just hit F5 and you’ll see a fully functional MVVM Silverlight app that uses WCF RIA Services.

The kicker is that you also get a Test project that uses the Microsoft Silverlight Testing Framework.

Features

New Features in v2:

An Installer that places the binaries, templates and snippets in all the right places.
- Copies binaries, libraries, samples and source code to one location
- Copies Visual Studio templates and code snippets to the correction location
- Registers the binaries so that SimpleMvvmToolkit appears in the Visual Studio Add References dialog.
Visual Studio project templates
- Project templates for Silverlight, Windows Phone and WPF, which include starter Locator, Model, ViewModel, View and ServiceAgent classes.
- A multi-project Visual Studio template that includes a Silverlight client, a Silverlight Unit Test project and a WCF RIA Services project.
The main sample now has Parts 2 and 3
- Part 2 demonstrates navigation, messaging, property associations, async
- Part 3 demonstrates using the toolkit with WCF RIA Services, including persistence with CRUD operations
Simplified and consolidated ViewModelLocator template which creates ViewModels on-demand.
- This allows Views to control the ViewModel lifetime, avoiding potential memory leaks
- Silverlight and Windows Phone apps use the same ViewModelLocator template
- The code snippet to insert injected (for dependency injection using MEF) ViewModels is more robust
Improved support for unit testing (with the Silverlight Unit Testing Framework – included in the Silverlight Toolkit)
- Includes an extension method for enqueuing conditional tasks with a timeout
Simpler and more robust MessageBus
- Now uses leak-proof eventing model so that unregistering for messages is no longer required
- ViewModelBase now includes helper methods for sending and receiving messages
GenericDelegateCommand supports parsing string parameters from XAML
- Plays nicer with CommandParameter in XAML

Other Features:

Support for Silverlight, WPF and Windows Phone 7
Helper classes, Visual Studio templates, code snippets
- Helpers: Model and view-model base classes, MessageBus,
  DelegateCommand, MEF Export attribute
- Templates: View-model, detail view-model,
  view-model locator, injected view-model locator
- C# Code Snippets: bindable property, vm locator, command
- XML Code Snippets: Blend event-trigger
Sample applications with step-by-step instructions
- End-to-end Silverlight Mvvm sample using WCF
- Simplified “Getting Started” sample
- Associated properties sample
- Async execution sample
- Enum to list conversion sample
- Message bus sample
- Navigation sample
- Dependency injection (MEF) with unit testing
Model and ViewModel base classes
Strongly typed data binding with lambda expressions
View-model locator service
DelegateCommand based on ICommand
AssociateProperties method to link view-model and model properties
Event-based facility for two-way communication between views and view-models
MessageBus for sending notifications in a loosely coupled fashion among view-models
Dependency injection (IoC) for unit testing using MEF (Managed Extensibility Framework)
IEditableDataObject support with deep cloning
Conversion of enums to lists for populating combo boxes
Async support with transparent marshaling to the UI thread
Built-in support for WCF RIA Services

What You Get

Prerequisites

1. Visual Studio 2010
Professional or Higher: http://www.microsoft.com/visualstudio/en-us/download
Express: http://www.microsoft.com/express/Download

2. Silverlight 4 Tools
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=b3deb194-ca86-4fb6-a716-b67c2604a139

3. Silverlight 4 Toolkit (April 2010)
http://silverlight.codeplex.com/releases/view/43528

4. Expression Blend 4 SDK (or Expression Blend 4 complete)
SL4: http://www.microsoft.com/downloads/en/details.aspx?FamilyID=d197f51a-de07-4edf-9cba-1f1b4a22110d&displaylang=en
WPF: http://www.microsoft.com/downloads/en/details.aspx?FamilyID=75E13D71-7C53-4382-9592-6C07C6A00207

5. For Windows Phone: Windows Phone Developer Tools RTW
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=04704acf-a63a-4f97-952c-8b51b34b00ce&displaylang=en

6. For RIA Services Development: WCF RIA Services V1.0 SP1 for Silverlight 4
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=330F6831-5B90-4315-B042-96127A4A7EFC&displaylang=en

7. For Samples: SQL Server 2008 Express (database with management tools)
http://www.microsoft.com/express/Database/InstallOptions.aspx

8. For Samples: Northwind Sample Database
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=06616212-0356-46a0-8da2-eebc53a68034&displaylang=en
- Make sure to attach the Northwind database to the SQLExpress instance

Getting Started

About the Author

What's Next?

I plan to put out additional blog posts and a series of screen casts on using the Simple MVVM Toolkit and exploring different features.

Updated Wiki: Home

tonysneed — Fri, 02 Mar 2012 16:25:43 GMT

Project Description

What’s Hot

Simple MVVM Toolkit now supports Silverlight 5.0 and Windows Phone 7.1! Project templates for both SL4 and SL5 are included, so you can use both. Samples have also been upgraded. Get it here.

Compare Simple MVVM Toolkit to MVVM Light Toolkit.

Take a look at the Getting Started screencast!

You can watch it now or download the screencast to watch it offline on your pc or mobile device.

View the Real-World MVVM with RIA Services Screencast:
Real-World MVVM Part 1: Streaming or Download (PC or mobile device)
Real-World MVVM Part 2: Streaming or Download (PC or mobile device)

Simple MVVM Toolkit can be downloaded from within Visual Studio by selecting the Tools menu, Extension Manager!

Simple MVVM Toolkit now has an installer! Just download and run it.

Simple MVVM Toolkit has some awesome Visual Studio project templates!

Here is what you get from the Silverlight project template. Just follow the instructions in ReadMe.txt.

Here is what you get from the RiaServices template. Just hit F5 and you’ll see a fully functional MVVM Silverlight app that uses WCF RIA Services.

The kicker is that you also get a Test project that uses the Microsoft Silverlight Testing Framework.

Features

New Features in v2:

An Installer that places the binaries, templates and snippets in all the right places.
- Copies binaries, libraries, samples and source code to one location
- Copies Visual Studio templates and code snippets to the correction location
- Registers the binaries so that SimpleMvvmToolkit appears in the Visual Studio Add References dialog.
Visual Studio project templates
- Project templates for Silverlight, Windows Phone and WPF, which include starter Locator, Model, ViewModel, View and ServiceAgent classes.
- A multi-project Visual Studio template that includes a Silverlight client, a Silverlight Unit Test project and a WCF RIA Services project.
The main sample now has Parts 2 and 3
- Part 2 demonstrates navigation, messaging, property associations, async
- Part 3 demonstrates using the toolkit with WCF RIA Services, including persistence with CRUD operations
Simplified and consolidated ViewModelLocator template which creates ViewModels on-demand.
- This allows Views to control the ViewModel lifetime, avoiding potential memory leaks
- Silverlight and Windows Phone apps use the same ViewModelLocator template
- The code snippet to insert injected (for dependency injection using MEF) ViewModels is more robust
Improved support for unit testing (with the Silverlight Unit Testing Framework – included in the Silverlight Toolkit)
- Includes an extension method for enqueuing conditional tasks with a timeout
Simpler and more robust MessageBus
- Now uses leak-proof eventing model so that unregistering for messages is no longer required
- ViewModelBase now includes helper methods for sending and receiving messages
GenericDelegateCommand supports parsing string parameters from XAML
- Plays nicer with CommandParameter in XAML

Other Features:

Support for Silverlight, WPF and Windows Phone 7
Helper classes, Visual Studio templates, code snippets
- Helpers: Model and view-model base classes, MessageBus,
  DelegateCommand, MEF Export attribute
- Templates: View-model, detail view-model,
  view-model locator, injected view-model locator
- C# Code Snippets: bindable property, vm locator, command
- XML Code Snippets: Blend event-trigger
Sample applications with step-by-step instructions
- End-to-end Silverlight Mvvm sample using WCF
- Simplified “Getting Started” sample
- Associated properties sample
- Async execution sample
- Enum to list conversion sample
- Message bus sample
- Navigation sample
- Dependency injection (MEF) with unit testing
Model and ViewModel base classes
Strongly typed data binding with lambda expressions
View-model locator service
DelegateCommand based on ICommand
AssociateProperties method to link view-model and model properties
Event-based facility for two-way communication between views and view-models
MessageBus for sending notifications in a loosely coupled fashion among view-models
Dependency injection (IoC) for unit testing using MEF (Managed Extensibility Framework)
IEditableDataObject support with deep cloning
Conversion of enums to lists for populating combo boxes
Async support with transparent marshaling to the UI thread
Built-in support for WCF RIA Services

What You Get

Prerequisites

1. Visual Studio 2010
Professional or Higher: http://www.microsoft.com/visualstudio/en-us/download
Express: http://www.microsoft.com/express/Download

2. Silverlight 4 Tools
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=b3deb194-ca86-4fb6-a716-b67c2604a139

3. Silverlight 4 Toolkit (April 2010)
http://silverlight.codeplex.com/releases/view/43528

5. For Windows Phone: Windows Phone Developer Tools RTW
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=04704acf-a63a-4f97-952c-8b51b34b00ce&displaylang=en

6. For RIA Services Development: WCF RIA Services V1.0 SP1 for Silverlight 4
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=330F6831-5B90-4315-B042-96127A4A7EFC&displaylang=en

7. For Samples: SQL Server 2008 Express (database with management tools)
http://www.microsoft.com/express/Database/InstallOptions.aspx

Getting Started

About the Author

What's Next?

I plan to put out additional blog posts and a series of screen casts on using the Simple MVVM Toolkit and exploring different features.

Updated Wiki: Prerequisites

tonysneed — Fri, 02 Mar 2012 00:02:12 GMT

Prerequisites

1. Visual Studio 2010 with Service Pack 1
Professional or Higher: http://www.microsoft.com/visualstudio/en-us/download
Or Express: http://www.microsoft.com/express/Download

2. Silverlight 4 Tools
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=b3deb194-ca86-4fb6-a716-b67c2604a139

3. Silverlight 5 Tools for VS 2010 SP1
http://www.microsoft.com/download/en/details.aspx?id=28358

4. Silverlight 4 Toolkit (April 2010)
http://silverlight.codeplex.com/releases/view/43528

5. Silverlight 5 Toolkit (December 2011)
http://silverlight.codeplex.com/releases/view/78435

7. Expression Blend Preview for Silverlight 5
http://www.microsoft.com/download/en/confirmation.aspx?id=9503

8. Windows Phone SDK 7.1
http://www.microsoft.com/download/en/details.aspx?id=27570

9. WCF RIA Services V1.0 SP1 for Silverlight 4
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=330F6831-5B90-4315-B042-96127A4A7EFC&displaylang=en

10. For Samples: SQL Server 2008 Express (database with management tools)
http://www.microsoft.com/express/Database/InstallOptions.aspx

Updated Wiki: Home

tonysneed — Thu, 01 Mar 2012 23:56:21 GMT

Project Description

What’s Hot

Simple MVVM Toolkit now supports Silverlight 5.0 and Windows Phone 7.1! Project templates for both SL4 and SL5 are included, so you can use both. Samples have been upgraded.

Compare Simple MVVM Toolkit to MVVM Light Toolkit.

Take a look at the Getting Started screencast!

You can watch it now or download the screencast to watch it offline on your pc or mobile device.

View the Real-World MVVM with RIA Services Screencast:
Real-World MVVM Part 1: Streaming or Download (PC or mobile device)
Real-World MVVM Part 2: Streaming or Download (PC or mobile device)

Simple MVVM Toolkit can be downloaded from within Visual Studio by selecting the Tools menu, Extension Manager!

Simple MVVM Toolkit now has an installer! Just download and run it.

Simple MVVM Toolkit has some awesome Visual Studio project templates!

Here is what you get from the Silverlight project template. Just follow the instructions in ReadMe.txt.

Here is what you get from the RiaServices template. Just hit F5 and you’ll see a fully functional MVVM Silverlight app that uses WCF RIA Services.

The kicker is that you also get a Test project that uses the Microsoft Silverlight Testing Framework.

Features

New Features in v2:

An Installer that places the binaries, templates and snippets in all the right places.
- Copies binaries, libraries, samples and source code to one location
- Copies Visual Studio templates and code snippets to the correction location
- Registers the binaries so that SimpleMvvmToolkit appears in the Visual Studio Add References dialog.
Visual Studio project templates
- Project templates for Silverlight, Windows Phone and WPF, which include starter Locator, Model, ViewModel, View and ServiceAgent classes.
- A multi-project Visual Studio template that includes a Silverlight client, a Silverlight Unit Test project and a WCF RIA Services project.
The main sample now has Parts 2 and 3
- Part 2 demonstrates navigation, messaging, property associations, async
- Part 3 demonstrates using the toolkit with WCF RIA Services, including persistence with CRUD operations
Simplified and consolidated ViewModelLocator template which creates ViewModels on-demand.
- This allows Views to control the ViewModel lifetime, avoiding potential memory leaks
- Silverlight and Windows Phone apps use the same ViewModelLocator template
- The code snippet to insert injected (for dependency injection using MEF) ViewModels is more robust
Improved support for unit testing (with the Silverlight Unit Testing Framework – included in the Silverlight Toolkit)
- Includes an extension method for enqueuing conditional tasks with a timeout
Simpler and more robust MessageBus
- Now uses leak-proof eventing model so that unregistering for messages is no longer required
- ViewModelBase now includes helper methods for sending and receiving messages
GenericDelegateCommand supports parsing string parameters from XAML
- Plays nicer with CommandParameter in XAML

Other Features:

Support for Silverlight, WPF and Windows Phone 7
Helper classes, Visual Studio templates, code snippets
- Helpers: Model and view-model base classes, MessageBus,
  DelegateCommand, MEF Export attribute
- Templates: View-model, detail view-model,
  view-model locator, injected view-model locator
- C# Code Snippets: bindable property, vm locator, command
- XML Code Snippets: Blend event-trigger
Sample applications with step-by-step instructions
- End-to-end Silverlight Mvvm sample using WCF
- Simplified “Getting Started” sample
- Associated properties sample
- Async execution sample
- Enum to list conversion sample
- Message bus sample
- Navigation sample
- Dependency injection (MEF) with unit testing
Model and ViewModel base classes
Strongly typed data binding with lambda expressions
View-model locator service
DelegateCommand based on ICommand
AssociateProperties method to link view-model and model properties
Event-based facility for two-way communication between views and view-models
MessageBus for sending notifications in a loosely coupled fashion among view-models
Dependency injection (IoC) for unit testing using MEF (Managed Extensibility Framework)
IEditableDataObject support with deep cloning
Conversion of enums to lists for populating combo boxes
Async support with transparent marshaling to the UI thread
Built-in support for WCF RIA Services

What You Get

Prerequisites

1. Visual Studio 2010
Professional or Higher: http://www.microsoft.com/visualstudio/en-us/download
Express: http://www.microsoft.com/express/Download

2. Silverlight 4 Tools
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=b3deb194-ca86-4fb6-a716-b67c2604a139

3. Silverlight 4 Toolkit (April 2010)
http://silverlight.codeplex.com/releases/view/43528

5. For Windows Phone: Windows Phone Developer Tools RTW
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=04704acf-a63a-4f97-952c-8b51b34b00ce&displaylang=en

6. For RIA Services Development: WCF RIA Services V1.0 SP1 for Silverlight 4
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=330F6831-5B90-4315-B042-96127A4A7EFC&displaylang=en

7. For Samples: SQL Server 2008 Express (database with management tools)
http://www.microsoft.com/express/Database/InstallOptions.aspx

Getting Started

About the Author

What's Next?

I plan to put out additional blog posts and a series of screen casts on using the Simple MVVM Toolkit and exploring different features.

New Comment on "Getting Started"

jlebrech — Mon, 17 Oct 2011 15:04:37 GMT

Hi, I'm trying to adapt this tutorial for Windows Phone. I can't get the trigger to work. How do I LoadProducts as soon as the page has loaded? And how would I use those in a ListBox. thanks.

New Comment on "Samples"

hjyanghj — Sun, 16 Oct 2011 09:51:45 GMT

Tony, In Messaging sample, I observed a strange phenomenon. Below are the steps. 1. Execute the program. 2. Click the "Increase Orders" button, when "Bill Gates" item is selected. 3. "Approve Increase" window show up, click "Yes" button. 4. MessageText "Order quantity of 1000 approved for Bill Gates" DO appear under the "Increase Orders" button. 5. Click "Increase Orders" button again, this time the MessageText should be disapeared, but is is STILL appear there. My question is: In your IncreaseOrders method, there is a statement "MessageVisibility = Visibility.Collapsed;", why has it no effect at all?

New Comment on "Getting Started"

hjyanghj — Sat, 15 Oct 2011 12:00:46 GMT

Nice documentation. It is nice to have included: how/when to insert item template and code/xaml snippet. Thanks a lot.

Updated Wiki: Getting Started

tonysneed — Sat, 10 Sep 2011 21:01:23 GMT

Getting Started

The easiest way to get started with the Simple Mvvm Toolkit is to create a new Visual Studio project using one of the project templates installed by the toolkit. Each project template creates a fully functioning MVVM application and includes a ReadMe.txt file with instructions for inserting your own classes using the Visual Studio item templates, code snippets and xml snippets. There are project templates for WPF, Silverlight and Windows Phone. These instructions will build a Silverlight MVVM application.

Watch or download the Getting Started screencast to see a demonstration of following the steps in this Getting Started exercise.

Open Visual Studio 2010, then select File, New Project.
- Under the Silverlight category, select the Mvvm sub-category
- Select the SimpleMvvmSilverlight project template
- Name the project Getting Started and click OK
The project already references the SimpleMvvmToolkit assembly.
- This reference can also be added manually through the Visual Studio Add References dialog.
- If references for Microsoft.Expression.Interactions and System.Windows.Interactivity are missing,
  you need to install the Microsoft Expression Blend SDK.
The project will contain folders for Locators, Models, Services, ViewModels and Views.
- You can use the files within each of these folders as examples, then simply remove them.
Start by adding a Product class to the Models folder.
- Derive the class from ModelBase<Product>, which adds data binding capabilities to Product.
- Use the mvvmprop code snippet to insert two properties:
  ProductId (int)
  ProductName (string)
- The code snippet will call the base method NotifyPropertyChanged,
  which accepts a lambda expression for the property name.
  - This provides a type-safe way to fire the PropertyChanged event,
    which is necessary for two-way data binding.
- NOTE: Code snippets have been around for quite a while and make it easier to write boilerplate code. Code snippets exist for many C# constructs, such as for, foreach, switch, etc. After inserting the code snippet, it acts like a form where you type a value and hit tab to go to the next field. You can create your own code snippets using a tool such as Snippet Designer, which you can install by going to Tools / Extensions Manager and searching for Snippet Designer in the Online Gallery.
```
public class Product : ModelBase<Product>
{
    private int productId;
    public int ProductId
    {
        get { return productId; }
        set
        {
            productId = value;
            NotifyPropertyChanged(m => m.ProductId);
        }
    }

    private string productName;
    public string ProductName
    {
        get { return productName; }
        set
        {
            productName = value;
            NotifyPropertyChanged(m => m.ProductName);
        }
    }
}
```
Next add an IProductServiceAgent interface to the Services folder.
- Include a LoadProducts method that returns a List<Product>
```
public interface IProductServiceAgent
{
    List<Product> LoadProducts();
}
```

Add a MockProductServiceAgent class that implements IProductServiceAgent.

Flesh out the LoadProducts method by creating a new List<Product> with a few products in it.

public class MockProductServiceAgent : IProductServiceAgent
{
    public List<Product> LoadProducts()
    {
        return new List<Product>
        {
            new Product { ProductId = 1, ProductName = "Chai" },
            new Product { ProductId = 2, ProductName = "Capuccino" },
            new Product { ProductId = 3, ProductName = "Latte" },
            new Product { ProductId = 4, ProductName = "Americano" },
            new Product { ProductId = 5, ProductName = "Machiato" }
        };
    }
}

Next we’re going to create a ProductListViewModel. But instead of just adding a class with this name to the project, we’ll use one of the Visual Studio item templates that ship with the Simple Mvvm Toolkit!
- Right-click the ViewModels folder and select Add New Item.
- Expand the Silverlight category on the left to select the Mvvm category.
- Select SimpleMvvmViewModel, enter ProductListViewModel.cs for the name, then click the Add button.
- What you get is a class which extends ViewModelBase<TViewModel>
- Replace the /* IXxxServiceAgent */ comment in the serviceAgent field with IProductServiceAgent.
- Replace the /* IXxxServiceAgent */ comment in the constructor with IProductServiceAgent.
```
public class ProductListViewModel : ViewModelBase<ProductListViewModel>
{
    // Add a member for IProductServiceAgent
    private IProductServiceAgent serviceAgent;

    // Default ctor
    public ProductListViewModel() { }

    // ctor that accepts IProductServiceAgent
    public ProductListViewModel(IProductServiceAgent serviceAgent)
    {
        this.serviceAgent = serviceAgent;
    }
```
- Using the mvvmprop code snippet add a Products property to the ProductListViewModel.
  - Make the property an ObservableCollection<Product>
- Add a LoadProducts method.
  - Call LoadProducts on serviceAgent and pass the result to the ctor of an ObservableCollection<Product>
  - Set the Products property to the ObservableCollection<Product>
```
private ObservableCollection<Product> products;
public ObservableCollection<Product> Products
{
    get { return products; }
    set
    {
        products = value;
        NotifyPropertyChanged(vm => vm.Products);
    }
}

public void LoadProducts()
{
    var products = serviceAgent.LoadProducts();
    Products = new ObservableCollection<Product>(products);
}
```

Open the ViewModelLocator.cs file, which resides in the Locators folder.

Use the mvvmlocator code snippet to add a property that creates the ProductListViewModel on demand.
- Set serviceAgent to a new MockProductServiceAgent

public class ViewModelLocator
{
    // Create ProductListViewModel on demand
    public ProductListViewModel ProductListViewModel
    {
        get
        {
            IProductServiceAgent serviceAgent = new MockProductServiceAgent();
            return new ProductListViewModel(serviceAgent);
        }
    }
}

Now that you’ve created a model and view-model, it’s time to create a view.

Right-click on the GettingStarted project to add a new Silverlight User Control named ProductListView.xaml
Move ProductListView.xaml to the Views folder
Add two rows to the grid, with a Button in the first row and a DataGrid in the second row.
Right-click on ProductListViewModel.xaml in the solution explorer and select Open With…
- Then choose the XML (Text) Editor and click OK (click Yes on the confirm dialog).
Place the cursor before the > symbol in the UserControl element, then right-click and select Insert Snippet.
- Select My XML Snippets / SimpleMvvm / mvvmxmlns, which inserts the blend namespaces
- Select My XML Snippets / SimpleMvvm / mvvmcontext, and bind the DataContext to the Locator’s ProductListViewModel property.
Lastly, provide a closing </Button> element and insert a blend event trigger to call the LoadProducts method on the Click event.
- Select My XML Snippets / SimpleMvvm / mvvmcommand, and type LoadProducts for the MethodName.
While you’re at it, go ahead and bind the ItemsSource property of the DataGrid with Path=Products
Double-click on ProductListView.xaml in the solution explorer to re-open the file in the designer. The XAML should look like this:

<UserControl x:Class="HelloSimpleMvvmSL.ProductListView"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:sdk="http://schemas.microsoft.com/winfx/2006/xaml/presentation/sdk"
    xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
    xmlns:ei="http://schemas.microsoft.com/expression/2010/interactions"
    mc:Ignorable="d"
    d:DesignHeight="300" d:DesignWidth="400"
    DataContext="{Binding Source={StaticResource Locator}, Path=ProductListViewModel}"
    >
    
    <Grid x:Name="LayoutRoot" Background="White">
        <Grid.RowDefinitions>
            <RowDefinition Height="46*" />
            <RowDefinition Height="254*" />
        </Grid.RowDefinitions>
      <Button Content="Load Products" Height="23" HorizontalAlignment="Left"
              Margin="12,12,0,0" Name="loadProductsButton"
              VerticalAlignment="Top"Width="95">
        <i:Interaction.Triggers>
          <i:EventTrigger EventName="Click">
            <ei:CallMethodAction
                    TargetObject="{Binding}"
                    MethodName="LoadProducts"/>
          </i:EventTrigger>
        </i:Interaction.Triggers>
      </Button>
        <sdk:DataGrid AutoGenerateColumns="True" Grid.Row="1" Height="214" 
            HorizontalAlignment="Left" Margin="12,14,0,0" Name="dataGrid1"
            VerticalAlignment="Top" Width="376"
            ItemsSource="{Binding Path=Products, Mode=TwoWay}" />
    </Grid>
</UserControl>

That’s all there is to it! Just set the content of MainPage.xaml to show the ProductListView, then press F5 to run the application.

Clicking on the Load Products button will display a list of products created by the MockProductServiceAgent and bound to the Products property of the ProductListViewModel.

<UserControl x:Class="HelloSimpleMvvmSL.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    d:DesignHeight="300" d:DesignWidth="400">

    <Grid x:Name="LayoutRoot" Background="White">
        <my:ProductListView xmlns:my="clr-namespace:HelloSimpleMvvmSL"/>
    </Grid>
    
</UserControl>

This Getting Started guide has walked you through the steps of building an MVVM Silverlight application using the Simple MVVM Toolkit. This includes using Visual Studio project and item templates, together with code and xml snippets, to produce service agents, models, view-models, and views. View-models are served up by a view-model locator, which creates a service agent and passes it to the ctor of the view-model. The DataContext of the view is set to a view-model property on the locator so that elements on the view can be bound to properties on the view-model.

In this exercise you used a mock service agent to create dummy model classes. To see how to connect this project to a WCF service for retrieving entities from a database, open projects in Samples\SimpleMvvm-Main and follow steps contained in the ReadMe files. Part 1 includes more information on using the toolkit, for example, concerning modal dialogs. Part 2 takes it a step further with navigation, messaging and async operations. Part 3 ports the solution to WCF RIA Services.

Updated Wiki: Programming Reference

tonysneed — Sun, 14 Aug 2011 19:53:39 GMT

Programming Reference

ViewModelBase

This class serves as the base class for all your view-models. It has a single property, IsInDesignMode, which returns true when a view that is bound to this view-model is being edited in a designer, which can either be Visual Studio or Expression Blend. To support designability, also referred to as Blendability, check this property in your view-model in order to supply data that will be displayed in design view. This makes it much easier for a designer, or a developer who is playing designer, to see a visual representation that is populated with sample or dummy data. This is important because live data will only be shown at runtime, and some controls, such as labels, cannot be easily manipulated by design tools unless there is some design-time data to hold it in place.

public abstract class ViewModelBase
{
    // Allows you to provide data at design-time (Blendability)
    public bool IsInDesignMode
    {
        get
        {
            return DesignerProperties.IsInDesignTool;
        }
    }
}

ModelBase<TModel>, ViewModelBase<TViewModel>

The toolkit includes two base classes, ModelBase<TModel> and ViewModelBase<TViewModel>, which support two-way data binding by implementing INotifyPropertyChanged. They do this by providing a NotifyPropertyChanged method that accepts a lambda expression indicating the property that has been changed. This is to address one of the drawbacks of the PropertyChanged event, which is that it accepts a string for the property name. However, because NotifyPropertyChanged accepts a lambda expression, it provides a compile-time check for the property name, which can catch errors when you change the property name and forget to change it in the call to NotifyPropertyChanged.

Another benefit of the NotifyPropertyChanged method is that it is always guaranteed to fire on the UI thread, because the InternalNotifyPropertyChanged method asks the current Dispatcher to see if we’re on the UI thread and, if not, calls BeginInvoke to marshal the call over to the UI thread. This behavior is required when you are setting properties asynchronously from a worker thread.

public abstract class ModelBase<TModel> : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged
    {
        add { propertyChanged += value; }
        remove { propertyChanged -= value; }
    }
    protected PropertyChangedEventHandler propertyChanged;

    protected virtual void NotifyPropertyChanged<TResult>
        (Expression<Func<TViewModel, TResult>> property)
    {
        // Fire PropertyChanged event
        BindingHelper.NotifyPropertyChanged(property, this, propertyChanged);
    }
    // Other members elided for clarity ...
}

public abstract class ViewModelBase<TViewModel> : ViewModelBase, INotifyPropertyChanged { ... }

internal static class BindingHelper
{
    // Defined as virtual so you can override if you wish
    public static void NotifyPropertyChanged<TModel, TResult>
        (Expression<Func<TModel, TResult>> property,
        object sender, PropertyChangedEventHandler propertyChanged)
    {
        // Convert expression to a property name
        string propertyName = ((MemberExpression)property.Body).Member.Name;

        // Fire notify property changed event
        InternalNotifyPropertyChanged(propertyName, sender, propertyChanged);
    }

    public static void InternalNotifyPropertyChanged(string propertyName, 
        object sender, PropertyChangedEventHandler propertyChanged)
    {
        if (propertyChanged != null)
        {
            // Always fire the event on the UI thread
            if (Deployment.Current.Dispatcher.CheckAccess())
            {
                propertyChanged(sender, new PropertyChangedEventArgs(propertyName));

            }
            else
            {
                Deployment.Current.Dispatcher.BeginInvoke(() => propertyChanged
                    (sender, new PropertyChangedEventArgs(propertyName)));
            }
        }
    }
}

Here is an example of calling NotifyPropertyChanged from a property setter in a view-model.

private bool canLoad;
public bool CanLoad
{
    get { return canLoad; }
    set
    {
        canLoad = value;
        NotifyPropertyChanged(m => m.CanLoad);
    }
}

Speaking of asynchronous programming, ViewModelBase<TViewModel> also includes a Notify method that fires a notification event by marshaling it to the UI thread if necessary. Further down this page you’ll learn about using notification events to handle two-way communication between a view and its view-model.

protected void Notify
    (EventHandler<NotificationEventArgs> handler,
    NotificationEventArgs e)
{
    if (handler != null)
    {
        InternalNotify(() => handler(this, e));
    }
}

protected void Notify<TOutgoing>
    (EventHandler<NotificationEventArgs<TOutgoing>> handler,
    NotificationEventArgs<TOutgoing> e)
{
    if (handler != null)
    {
        InternalNotify(() => handler(this, e));
    }
}

protected void Notify<TOutgoing, TIncoming>
    (EventHandler<NotificationEventArgs<TOutgoing, TIncoming>> handler,
    NotificationEventArgs<TOutgoing, TIncoming> e)
{
    if (handler != null)
    {
        InternalNotify(() => handler(this, e));
    }
}

private void InternalNotify(Action method)
{
    // Always fire the event on the UI thread
    if (UIDispatcher.Current.CheckAccess())
        method();
    else
        UIDispatcher.Current.BeginInvoke(method);
}

ViewModelDetailBase<TViewModel, TModel>

This base class implements IEditableObject to support editing an entity and either committing or rolling back changes. A typical scenario would be an Edit dialog or page that will commit changes when the user clicks OK or roll them back when the user clicks Cancel. Calling the edit methods will only be necessary if editing is not already enabled by another means, such as a data form or in the base class of your model entities, as is the case with RIA Services. The way ViewModelDetailBase does this is with an Model property that will either point to a cloned version of the entity (on BeginEdit) or to the original version (on CancelEdit). In EndEdit it will copy values from the cloned object over to the original.

public abstract class ViewModelDetailBase<TViewModel, TModel>
    : ViewModelBase<TViewModel>, IEditableObject
    where TModel : INotifyPropertyChanged
{
    public TModel Model
    {
        get { return model; }
        set
        {
            model = value;
            BindingHelper.InternalNotifyPropertyChanged("Model",
                this, base.propertyChanged);
        }
    }
    private TModel model;

    // Other members elided for clarity ...

    private TModel Original;
    private TModel Copy;

    public void BeginEdit()
    {
        // Throw an exception if Entity not supplied
        if (Model == null)
        {
            throw new InvalidOperationException("Entity must be set");
        }

        // Copy entity
        Original = Model;
        Copy = Model.Clone();

        // Point entity to the copy
        Model = Copy;
    }

    public void CancelEdit()
    {
        // Point entity to original
        Model = Original;
    }

    public void EndEdit()
    {
        // Tranfer values from copy to original
        Copy.CopyValuesTo(Original);

        // Point entity to original
        Model = Original;
    }
}

The Clone and CopyValuesTo methods are implemented as extension methods in the Extensions class and can be brought into scope by inserting a using directive for the namespace, SimpleMvvmToolkit.ModelExtensions. Clone uses the DataContractSerializer to serialize the object to and from a memory stream. It will work with entities that do not have the [DataContract] attribute by serializing all public properties.

public static class Extensions
{
    public static T Clone<T>(this T obj)
    {
        T copy = default(T);
        using (MemoryStream stream = new MemoryStream())
        {
            var ser = new DataContractSerializer(typeof(T));
            ser.WriteObject(stream, obj);
            stream.Position = 0;
            copy = (T)ser.ReadObject(stream);
        }
        return copy;
    }

    public static void CopyValuesTo<T>(this T source, T dest)
    {
        var properties = typeof(T).GetProperties(BindingFlags.Public | BindingFlags.Instance)
            .Where(p => p.CanRead && p.CanWrite);

        foreach (var property in properties)
        {
            if (property.GetSetMethod() == null) continue;
            property.SetValue(dest, property.GetValue(source, null), null);
        }
    }
}

There is also an AssociateProperties method that will propagate changes from a model property to a view-model property, so that updates to the model will be reflected in UI elements that are bound to the corresponding view-model properties.

protected virtual void AssociateProperties<TModelResult, TViewModelResult>
    (Expression<Func<TModel, TModelResult>> modelProperty,
        Expression<Func<TViewModel, TViewModelResult>> viewModelProperty)
{
    // Convert expressions to a property names
    string modelPropertyName = ((MemberExpression)modelProperty.Body).Member.Name;
    string viewModelPropertyName = ((MemberExpression)viewModelProperty.Body).Member.Name;

    // Propagate model to view-model property change
    Model.PropertyChanged += (s, ea) =>
    {
        if (ea.PropertyName == modelPropertyName)
        {
            BindingHelper.InternalNotifyPropertyChanged(viewModelPropertyName,
                this, base.propertyChanged);
        }
    };
}

Here is an example of a CustomerViewModel class that transforms properties on a Customer model. FirstName and LastName are exposed as a single CustomerName property, and IsActive is used to expose an OrdersVisibility property. CustomerViewModel calls AssociateProperties in the setter of a Customer property, so that changes to the Customer model properties will be reflected in UI elements that are bound to the CustomerName and OrdersVisibility properties.

public class CustomerViewModel : ViewModelDetailBase<CustomerViewModel, Customer>
{
    public Customer Customer
    {
        get
        {
            return Model;
        }
        set
        {
            Model = value;

            // Associate model and view-model properties
            AssociateProperties(m => m.FirstName, vm => vm.CustomerName);
            AssociateProperties(m => m.LastName, vm => vm.CustomerName);
            AssociateProperties(m => m.IsActive, vm => vm.OrdersVisibility);
        }
    }

    public string CustomerName
    {
        get
        {
            // Concatenate first and last name
            return string.Format("{0} {1}",
                Model.FirstName, Model.LastName);
        }
    }

    public Visibility OrdersVisibility
    {
        get
        {
            // Show orders only for active customers
            return Model.IsActive ? Visibility.Visible : Visibility.Collapsed;
        }
    }
}

NotificationEventArgs

When a view-model wishes to communicate with a view, it should do so in a loosely coupled manner. The view-model should not reference the view or be aware of it in any way. This presents somewhat of a quandary for many developers. One approach is to use a message bus for communication between the view-model and the view. To my mind, that is a bit too loose, because the view already holds a reference to the view-model. Another approach is to use a service represented by an interface. The view-model then holds on to a reference to the view via the service interface. This is better than a direct reference but seems still too tight to me. I prefer to use events as the communication mechanism because they offer finer granularity than interfaces and are more direct than a message bus. Plus they are easy for developers to understand and implement.

There are three versions of NotificationEventArgs. The non-generic version simply has a string Message property. There also is a generic version that accepts a <TOutgoing> type argument, which is an additional data payload passed by the view-model back to the view. This can be an Exception or any other type. And there another generic version which has a Completed property that is an Action<TIncoming>, which the view-model sets to a completion callback method, so that the view can call back the view-model and pass a data payload.

public class NotificationEventArgs : EventArgs
{
    public NotificationEventArgs() { }
    public NotificationEventArgs(string message)
    {
        Message = message;
    }

    // Message
    public string Message { get; protected set; }
}

public class NotificationEventArgs<TOutgoing> : NotificationEventArgs
{
    public NotificationEventArgs() { }
    public NotificationEventArgs(string message) : base(message) { }
    public NotificationEventArgs(string message, TOutgoing data)
        : this(message)
    {
        Data = data;
    }

    // Data
    public TOutgoing Data { get; protected set; }
}

public class NotificationEventArgs<TOutgoing, TIncoming> : NotificationEventArgs<TOutgoing>
{
    public NotificationEventArgs() { }
    public NotificationEventArgs(string message) : base(message) { }
    public NotificationEventArgs(string message, TOutgoing data)
        : base(message, data) { }
    public NotificationEventArgs(string message, TOutgoing data, Action<TIncoming> completed)
        : this(message, data)
    {
        Completed = completed;
    }
        
    // Completion callback
    public Action<TIncoming> Completed { get; protected set; }
}

Here is an example of a view-model firing a one-way notification event.

public class ProductListViewModel : ViewModelBase<ProductListViewModel>
{
    // By convention we'll suffix each notification event with 'Notice'
    public event EventHandler<NotificationEventArgs<Exception>> ErrorNotice;

    private void NotifyError(string message, Exception error)
    {
        // Notify view of an error
        if (ErrorNotice != null)
        {
            ErrorNotice(this, new NotificationEventArgs<Exception>(message, error));
        }
    }
}

However, we can make this more concise by taking advantage of the Notify method in ViewModelBase, which checks if the event is null (meaning it has no subscribers) and transparently marshals the call to the UI thread if necessary.

private void NotifyError(string message, Exception error)
{
    // Notify view of an error
    Notify(ErrorNotice, new NotificationEventArgs<Exception>(message, error));
}

Here is an example of a view-model firing a two-way notification event.

public class ProductListViewModel : ViewModelBase<ProductListViewModel>
{
    // By convention we'll suffix each notification event with 'Notice'
    public event EventHandler<NotificationEventArgs<bool, bool>> ProductAvailableNotice;
 
    private void ProductAvailable(bool available, Exception error)
    {
        // Notify view that product is available        Notify(ProductAvailableNotice, new NotificationEventArgs<bool, bool>
            (null, available, 
            confirm => { if (confirm) /* place order */; }));
    }
}

The view can respond handle the event in its code-behind class, supplying the <TIncoming> argument, which in this case is a boolean indicating that the user confirmed the order.

public partial class ProductListView : UserControl
{
    // Reference view model
    ProductListViewModel vm;

    public ProductListView()
    {
        InitializeComponent();

        // Get model from data context
        vm = (ProductListViewModel)DataContext;

        // Subscribe to notifications from the model
        vm.ErrorNotice += OnErrorNotice;
        vm.ProductAvailableNotice += OnProductAvailableNotice;
    }

    void OnErrorNotice(object sender, NotificationEventArgs<Exception> e)
    {
        MessageBox.Show(e.Message, "Error", MessageBoxButton.OK);
        Debug.WriteLine(e.Data.ToString());
    }

    void OnProductAvailableNotice(object sender, NotificationEventArgs<bool, bool> e)
    {
        // Product is available
        if (e.Data)
        {
            // Show OrderProductView dialog
            OrderProductView orderProductView = new OrderProductView();
            var orderProductVm = (OrderProductViewModel)orderProductView.DataContext;
            orderProductVm.Product = vm.SelectedProduct;
            orderProductView.Closed += (s, ea) =>
            {
                if (orderProductView.DialogResult == true)
                {
                    // Notify view model to order product
                    e.Completed(true);
                }
            };
            orderProductView.Show();
        }
        else
        {
            MessageBox.Show("Product is unavailable.",
                "Product Availability", MessageBoxButton.OK);
        }
    }
}

DelegateCommand

SimpleMvvmToolkit also contains generic and non-generic versions of a DelegateCommand class. This is typically used to supply an ICommand property on the view-model, which the view can reference to bind the Command property of a ButtonBase-derived class. This is to support scenarios where you might have a method on your view-model that accepts a parameter that is not already exposed as a property on the view-model.

public class DelegateCommand<T> : ICommand
{
    private Func<T, bool> canExecute;
    private Action<T> executeAction;

    public event EventHandler CanExecuteChanged;

    public DelegateCommand(Action<T> executeAction,
        Func<T, bool> canExecute)
    {
        this.executeAction = executeAction;
        this.canExecute = canExecute;
    }

    public DelegateCommand(Action<T> executeAction)
    {
        this.executeAction = executeAction;
        this.canExecute = x => true;
    }

    public void RaiseCanExecuteChanged()
    {
        if (CanExecuteChanged != null)
        {
            CanExecuteChanged(this, EventArgs.Empty);
        }
    }

    public bool CanExecute(object parameter)
    {
        if (parameter == null) return true;
        T param = ConvertParameter(parameter);
        return canExecute == null ? true : canExecute(param);
    }

    public void Execute(object parameter)
    {
        T param = ConvertParameter(parameter);
        executeAction(param);
    }

    // Convert parameter to expected type, parsing if necessary
    private T ConvertParameter(object parameter)
    {
        string exceptionMessage = string.Format("Cannot convert {0} to {1}",
            parameter.GetType(), typeof(T));

        T result = default(T);
        if (parameter != null && parameter.GetType() == typeof(T))
        {
            result = (T)parameter;
        }
        else if (parameter is string)
        {
            MethodInfo mi = (from m in typeof(T).GetMethods(BindingFlags.Static | BindingFlags.Public)
                                where m.Name == "Parse" && m.GetParameters().Count() == 1
                                select m).FirstOrDefault();
            if (mi != null)
            {
                try
                {
                    result = (T)mi.Invoke(null, new object[] { parameter });
                }
                catch (Exception ex)
                {
                    if (ex.InnerException != null) throw ex.InnerException;
                    else throw new InvalidCastException(exceptionMessage);
                }
            }
        }
        else
        {
            throw new InvalidCastException(exceptionMessage);
        }
        return result;
    }
}

Use the mvvmvommand code snippet to insert a command that will execute a method on the ViewModel. The ctor for DelegateCommand<T> also accepts a delegate for a method that accepts T and returns bool. Notice that the setter for the Amount property calls the RaiseCanExecuteChanged method so that the CanExecute method will be evaluated and the button will be enabled or disabled depending on whether the method returns true or false.

#region Properties

private int amount;
public int Amount
{
    get { return amount; }
    set
    {
        amount = value;
        NotifyPropertyChanged(m => m.Amount);

        // Raise can execute changed event on command
        AddCommand.RaiseCanExecuteChanged();
    }
}

private int total;
public int Total
{
    get { return total; }
    set
    {
        total = value;
        NotifyPropertyChanged(m => m.Total);
    }
}

#endregion

#region Methods

void Add(int num)
{
    Total = Amount + num;
}

bool CanAdd(int num)
{
    return Amount > 0;
}

#endregion

#region Commands

private DelegateCommand<int> addCommand;
public DelegateCommand<int> AddCommand
{
    get { return addCommand ?? (addCommand = new DelegateCommand<int>(Add, CanAdd)); }
    private set { addCommand = value; }
}

#endregion

The view can then bind the Command of a Button to the AddCommand on the view-model, specifying a CommandParameter to pass to the Add method.

<Button Content="Add 1"
        Command="{Binding AddCommand}"
        CommandParameter="1"/>

Here is a sample application that demonstrates the use of commands with Simple Mvvm Toolkit.

Blend EventTrigger / Action

While I support this approach, I find that it is not needed most of the time because you will generally have controls in the view that are bound to properties on the view-model. A parameterless method on the view-model can simply reference these properties, freeing you to use an blend-style event trigger that uses a CallMethodAction. This relieves you from having a bunch of code in your view-model just to support command-binding. Event triggers can respond to any event, not just click, and there’s no need to call RaiseCanExecuteChanged.

Here is a XAML snippet that calls the LoadProducts method on the view-model on the SelectionChanged event of a combo box.

xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
xmlns:ei="http://schemas.microsoft.com/expression/2010/interactions"

<!-- Bind ItemsSource to Categories -->
<!-- Bind SelectedItem to SelectedCategory -->
<ComboBox Height="23" Name="categoriesComboBox" Width="149" 
            DisplayMemberPath="CategoryName" 
            ItemsSource="{Binding Path=Categories}" 
            SelectedItem="{Binding Path=SelectedCategory, Mode=TwoWay}" Margin="0,5">
    <!-- Call LoadProducts on SelectionChanged event -->
    <i:Interaction.Triggers>
        <i:EventTrigger EventName="SelectionChanged">
            <ei:CallMethodAction 
                TargetObject="{Binding}"
                MethodName="LoadProducts"/>
        </i:EventTrigger>
    </i:Interaction.Triggers>
</ComboBox>

The toolkit comes with two XML code snippets you can use to insert namespaces and the event trigger: mvvmxmlns and mvvmtrigger. However, Visual Studio does not support using code snippets in a XAML file, you you need to open the file with the Visual Studio XML Editor (right-click, Open With, XML Text Editor). Then place the cursor where you want to use the snippet, right-click and select Insert Snippet).

MessageBus

Sometimes you need to pass messages among view-models in your application. A good example would be when you want to navigate to a particular view based on some business logic. It would not be a good idea to reference the main view-model directly from another view-model. Doing so would create interdependencies between view-models that would be difficult to maintain (a phenomenon referred to as spaghetti code). This is where a message bus (also called an event mediator or aggregator) comes in handy. The CustomerViewModel, for example, can then send a message to the message bus using a specific token, and the MainPageViewModel can subscribe to receive a message whenever someone sends a message with this same token to the message bus. Message tokens are simply strings that can be defined as constants in a class.

To make it easy to send and receive messages via the MessageBus, ViewModelBase<TViewModel> has two helper methods: RegisterToReceiveMessages and SendMessage. Here is a Save method in the CustomerViewModel that posts a message to the MessageBus using a token defined as a string constant in the MessageTokens class. The message content is simply a NotificationEventArgs object, which in this case simply passes the name of the page we want to navigate to.

public void Save()
{
    SendMessage(MessageTokens.Navigation,
        new NotificationEventArgs(PageNames.Home));
}

The MainPageViewModel subscribes to receive messages with the MessageTokens.Navigation token. When a message arrives at the MessageBus with this token, the MessageBus will call the method supplied to the Register method. In this case the OnNavigationRequested method will be called, which will navigate to the specified page.

public class MainPageViewModel : ViewModelBase<MainPageViewModel>
{
    public MainPageViewModel()
    {            RegisterToReceiveMessages(MessageTokens.Navigation, OnNavigationRequested);
    }

    void OnNavigationRequested(object sender, NotificationEventArgs e)
    {
        Navigate(e.Message);
    }
}

Because the MessageBus implements a leak-proof eventing model, there is no need for the MainPageViewModel to unregister for receiving messages. Message receivers are weakly referenced by the MessageBus, so they can be garbage collected at any time.

That’s all there is to it! As with direct notifications, you can pass additional data by specifying a TOutgoing argument on NotificationEventArgs. And you can even have the message recipient call back the sender by passing in a callback method with a TIncoming argument. Strongly-typed, loosely-coupled two-way communication. Cool.

ViewModelLocator

There are many ways to create ViewModels. But for a better design-time experience it’s a good idea to bind the DataContext of the View directly to a ViewModel. There are times, however, when you want to supply a service agent to the ViewModel’s constructor, which means you cannot create the ViewModel in the XAML of the View. What you need to solve this problem is a ViewModelLocator. Luckily for you, the toolkit comes with a Visual Studio item template. Simply add a new item to the project and select SimpleMvvmViewModelLocator from the dialog. Then use the mvvmlocator code snippet to insert a property that creates a ViewModel on demand while supplying a service agent to the ViewModel’s ctor.

public class ViewModelLocator
{
    // Create CustomerViewModel on demand
    public CustomerViewModel CustomerViewModel
    {
        get
        {
            ICustomerServiceAgent serviceAgent = new MockCustomerServiceAgent();
            return new CustomerViewModel(serviceAgent);
        }
    }
}

An instance of the ViewModelLocator is stored in the resource dictionary of App.xaml and identified with a key of “Locator”.

<Application xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
             x:Class="SimpleMvvmSilverlight.App">
    <Application.Resources>
        <vm:ViewModelLocator xmlns:vm="clr-namespace:SimpleMvvmSilverlight"
            x:Key="Locator" />
    </Application.Resources>
</Application>

Then you need to bind the DataContext of the View using a StaticResource with the “Locator” key, specifying the CustomerViewModel property for the Path.

<UserControl x:Class="SimpleMvvmSilverlight8.CustomerView"
    DataContext="{Binding Source={StaticResource Locator}, Path=CustomerViewModel}">

ServiceAgentExportAttribute, IServiceAgentMetadata, AgentType

These classes support using Dependency Injection (also called Inversion of Control) to specify which service agent to use in a view-model locator. This is useful for executing unit tests with mock data so that they run faster and do not depend on external factors such as the availability of services or data stores. The simplest way to implement dependency injection is to use Managed Extensibility Framework (MEF), which ships with Silverlight out of the box. The way you do this is to define a custom export attribute which includes a property you can use to as metadata to identify which class you want to materialize. A full discussion of MEF is beyond the scope of this documentation, but you can find more information on my blog, including a screencast, slides and code samples.

The way you use these classes is to decorate service agents with the ServiceAgentExport attribute, passing the service agent interface as the contract type and an AgentType enum value (which can be Unspecified, Real or Mock).

[ServiceAgentExport(typeof(ICustomerServiceAgent), AgentType = AgentType.Mock)]
public class MockItemListServiceAgent : IItemListServiceAgent
{
    public void GetItems(Action<Item, Exception> completed)
    {
        // Use mock data for Customer ...
    }
}

You can then add an “injected” view-model locator using the SimpleMvvmViewModelInjectedLocator Visual Studio item template that comes with the toolkit. This class as an AgentType property which unit tests can set to Mock. There is also a ServiceAgents property with an ImportMany MEF attribute. It uses a Lazy<T, TMetadata> type to only get service agents with a particular AgentType used in its ServiceAgentExport attribute. The constructor of the view-model asks MEF to set the ServiceAgents property.

public class InjectedViewModelLocator
{
    static InjectedViewModelLocator()
    {
        // Expose parts in the current XAP to MEF
        if (!DesignerProperties.IsInDesignTool)
            CompositionHost.Initialize(new DeploymentCatalog());
    }

    // TODO: Change agent type to Real
    private AgentType agentType = AgentType.Mock;
    public AgentType AgentType
    {
        get { return agentType; }
        set { agentType = value; }
    }

    public InjectedViewModelLocator()
    {
        // Inject service agents at runtime
        if (!DesignerProperties.IsInDesignTool)
        {
            CompositionInitializer.SatisfyImports(this);
            Debug.Assert(this.ItemListViewModel != null,
                string.Format("No IItemListServiceAgent has ServiceAgentExport with AgentType = {0}", agentType));
        }
    }

    // Create MainPageViewModel on demand
    public MainPageViewModel MainPageViewModel
    {
        get { return new MainPageViewModel(); }
    }

    // Create ItemListViewModel on demand
    [ImportMany]
    public Lazy<IItemListServiceAgent, IServiceAgentMetadata>[] ItemListServiceAgents { get; set; }
    public ItemListViewModel ItemListViewModel
    {
        get
        {
            var serviceAgent = ItemListServiceAgents
                .Where(sa => sa.Metadata.AgentType == agentType).FirstOrDefault();
            ItemListViewModel viewModel = null;
            if (serviceAgent != null) viewModel = new ItemListViewModel(serviceAgent.Value);
            else if (DesignerProperties.IsInDesignTool) viewModel = new ItemListViewModel();
            return viewModel;
        }
    }
}

You can then add a Silverlight Unit Test Application to your project (provided you’ve installed the Silverlight Toolkit) and create a test that sets AgentType on InjectedViewModelLocator to Mock before executing the test. Here is an example which also plays nice with the asynchronous nature of the LoadItems mehod. The unit test app requires that to run the app to execute the tests.

[TestClass]
public class ItemListViewModelTests : SilverlightTest
{
    // Mock data
    private List<Item> mockItems = MockItems.GetItems();

    // Add ViewModel field
    ItemListViewModel viewModel;

    // Initialize ViewModel
    public ItemListViewModelTests()
    {
        // Create locator
        var locator = new InjectedViewModelLocator();
        locator.AgentType = AgentType.Mock;

        // Get ViewModel
        this.viewModel = locator.ItemListViewModel;
        Assert.IsNotNull(viewModel, "ServiceAgent not injected for ViewModel");
    }

    [TestMethod, Asynchronous]
    public void LoadItemsTest()
    {
        // Completion flag
        bool completed = false;

        // Handle error
        viewModel.ErrorNotice += (s, ea) => Assert.Fail(ea.Data.Message);

        // Handle property change
        viewModel.PropertyChanged += (s, ea) =>
        {
            string propName = this.GetPropertyName<ItemListViewModel,
                ObservableCollection<Item>>(vm => vm.Items);
            if (ea.PropertyName == propName
                && viewModel.Items != null) completed = true;
        };

        // Call ViewModel method
        EnqueueCallback(() => viewModel.LoadItems());

        // Wait for completion with timeout
        int timeoutSeconds = 10; //Debugging: Timeout.Infinite
        this.EnqueueConditional(() => completed, timeoutSeconds);

        // Perform Asserts
        EnqueueCallback(() =>
            {
                // Categories has been set to 8
                Assert.IsNotNull(viewModel.Items);
                Assert.Equals(viewModel.Items.Count, 8);
            });

        // Complete test
        EnqueueTestComplete();
    }
}

Happy coding!

New Comment on "WCF RIA Services"

BravcM — Thu, 02 Jun 2011 09:43:34 GMT

Very, very good! At least one tutorial which covers MVVM, Entity Framework and WCF RIA Services! Perhaps in reflection how to separate Products View as dynamic view (module) which is loaded on demand from xap file (using MEF)? Thank you very much!

New Comment on "Getting Started"

tonysneed — Wed, 01 Jun 2011 22:06:51 GMT

@Dolemike: Glad you figured it out. :-) I will need to do a Getting Started for WP7.

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