Question

In a Windows 8 style app I have a View (or page) which is made up of several other Sub-Views.

Each of these has an associated ViewModel and they are defined and bounded via the MVVM Light ViewModelLocator

I then have a View2 which is made up of other Sub-Views which, again, are defined and bounded via the MVVM Light ViewModelLocator

What I want to do is to place instances of the View and View2 controls into a List on a MasterViewModel and then bind this list to a GridView on a MasterView file.

Each of the instances of View and View2 should render as they do if you were to create a single instance without placing it into a list.

What I have tried to do is create a List of Pages (as all views are instances of this type) and bind the GridView to this, but when I run the app the GridView appears empty.

I have seen an examples that use a DataTemplateSelector (http://www.wiredprairie.us/blog/index.php/archives/1705) and apply a DataTemplate to each of the items in the MasterView list.

I understand what this does, but what I don’t understand is how to create a DataTemplate for a View that is made up of other Views.

I’m sure I am overlooking something and / or just making this harder than it needs to be!
Thank you for any help 🙂

Answer 1

Normally in this case, you would be binding a list to a set of ViewModels, not views, and the data template selector (or ValueConverter depending on your flavour) would select and instantiate a view suited to the view model.

So if ViewA uses ViewModelA : ISubViewViewModel, and ViewB uses ViewModelB : ISubViewModel then your main ViewModel would contain a List<ISubViewModel> which has a set of ViewModelA & ViewModelB within it. The main view’s ListBox is bound to the List<ISubViewModel> and the data template selector / ValueConverter resolves ViewA for ViewModelA‘s and ViewB for ViewModelB‘s.

Hope that makes sense, it’s about as hard to describe the solution as it probably was to describe the problem. 🙂