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My approach to View-First ViewModel creation has evolved over time.  I have constructed ViewModels in code-behind.  I have instantiated ViewModels in the resources sectoin of the view. I have used Prism to resolve ViewModels via Dependency Injection. I have created attached properties that use Dependency Injection containers underneath.  Of all these approaches, I continue to find issues either in composability, blendability or maintainability. 

Thanks to everyone who came out last night, there were a lot of good question.  I was pleased to claim victory over Chicago traffic.

Yes, we did go to Fogo de Chao afterwards.  I’ve been invited back to hit some more advanced MVVM topics or perhaps a “MEF and Silverlight” show.

In the first part of the article I described the way to implement the deep linking feature in MVVM-based Silverlight application.

In this post I am going to describe two other important functionalities that  should be implemented to achieve great level of search engine optimization. First on is sitemaps and second one is html content providing.

The View Model Style pattern allows a programmer to create an application that has no UI (user interface). The programmer only creates a ViewModel and a Model. A designer with no programming ability at all, is then able to create the View (UI) in Microsoft Expression Blend 4 (or higher). If you are new to the View Model Style pattern, it is suggested that you read Silverlight View Model: An (Overly) Simplified Explanation for an introduction.

Isolated storage is a file system. It is called "isolated" because it is rooted to a specific directory which provides the sandbox required for browser security. [...]

Creating a base generic repository allowed me to centralize common IsolatedStorageFile operations that would be needed any time I wanted to save, retrieve, or delete any type of object from Isolated Storage in my application while still being strongly typed.

For the most part combining WCF RIA Services with the MVVM pattern is easy. One area of difficulty is in exposing collections of entities from the ViewModel. This post is going to show some of the current possibilities including my favorite solution, the PagedCollectionView. In two follow up posts I will be discussing some more advanced PagedCollectionView examples and then some future possibilities.

This sample application is the result of my initiative to learn Silverlight and WCF RIA Services. With my background of using WPF and MVVM for the past several years, I found that there is a lack of sample LOB applications that can combine the latest Silverlight enhancements with MVVM. This three part article series is my effort at creating such a sample. The choice of an issue tracking application comes from David Poll's PDC09 talk, and the design architecture is from Shawn Wildermuth's blog posts.

The issue there is as old as the DataGrid (that’s not very old but still): SelectedItem (singular) is a DependencyProperty and can be databound to a property in the ViewModel. SelectedItems (plural) is not a DependencyProperty.

Thankfully the answer is very simple: Use EventToCommand to call a Command in the ViewModel, and pass the SelectedItems collection as parameter.

Microsoft Extensibility Framework or MEF is one of the great features in Silverlight, designed around making Silverlight applications more extensible generally and provides a much more complete story for the separation of concerns. MEF then begs the question 'Why we care?' and 'What can MEF really do?' and we will address that here.