CODEWITHSUNDEEP
mvvmbindingexpression-blend
Edward Tanguay
Edward Tanguay

Reputation: 193282

How to do View/ViewModel binding in MVVM apps so Expression Blend can be used?

When you use the MVVM Visual Studio Template, then your ViewModels are bound to your Views' DataContexts in the App.xaml.cs something like this:

MainView mainView = new MainView();
mainView.DataContext = new MainViewModel();
mainView.Show();

And if you use Composite Application Library, then you have your Views and ViewModels being bound together in your Bootstrapper/Container/ServerLocator, etc.

In any case, when you open these projects in Expression Blend and open a View XAML file, Expression blend doesn't know which ViewModel belongs to which View since this binding is done in code as in above instances.

You can of course set a DataObjectProvider in your XAML so Expression Blend knows where to get its data for that View but this breaks MVVM and the decoupling pattern since your View is now hard-wired to a specific ViewModel. It this how designers normally work with Expression Blend on projects that are more than a little demo?

So for those of you using the MVVM pattern and who have designers who use Expression Blend, how are you keeping your View/ViewModel binding structured so that Expression Blend can know which ViewModel belongs to which Views?

Upvotes: 2

Views: 1321

Answers (1)

ima
ima

Reputation: 8255

Blend does load and execute code, even though it doesn't run the application. Load some sample DataContext if DesignerProperties.GetIsInDesignMode(...) in a view constructor or another more appropriate method.

Upvotes: 2

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