Question

Please assist with MVVM design/understanding problem.

Given that we have a Windows Phone app with following UI structure:

MainPage.xaml body:

<views:PanoramaView/>

DataContext is set via MVVM Light view-model locator to a static MainViewModel class instance.

Views/PanoramaView.xaml body:

<UserControl.DataContext>
        <ViewModels:PanoramaViewModel/>
</UserControl.DataContext>

<StackPanel x:Name="LayoutRoot">
        <controls:Panorama Background="{Binding PanoramaBackgroundBrush}"
                           ItemsSource="{Binding PanoramaItems}"
                           ItemTemplate="{StaticResource panoramaItemTemplate}"
                           />
</StackPanel>

At that point I have stumbled upon a question – What should I do in case I want all my PanoramaItems to be comprised of a different user controls? If I define a panorama item template, I doom all of them to be alike. But my intention is to have serveral, compeltely different panorama items. I wanted to have a class (presumably PanoramaViewModel) that would allow me control which panorama items are displayed at a given moment of time.

So there has to be a way for me to still stick to MVVM, but to be able to instantiate new Views(Panorama Items) and inject them into a PanoramaItems collection of my PanoramaViewModel. Where and how do I do that?

Answer 1

You have to define resource key to define a data template with view setter for the view item being rendered for the different view model class types, and derive VM classes from a common base class (PanoramaViewModel, i.e)