Loading XAML at runtime using the MVVM pattern in WPF

Question

This is a question that extends from the originally posted here: Link to loading-xaml through runtime

I\'m working on a WPF MVVM application that loads XAML content

Answer 1

I have a working solution now and I'd like to share it. Unfortunately I did not get rid of code-behind completely but it works as I expect it to. Here is how it works(simplified):

I have my simplified ViewModel:

public class MyViewModel : ViewModelBase
{
   //This property implements INPC and triggers notification on Set
   public string XamlViewData {get;set;}

   public ViewModel()
   {
      GetXamlFormData();  
   }

   //Gets the XAML Form from an external source (e.g. Database, File System)
   public void GetXamlFormData()
   {
       //Set the Xaml String property
       XamlViewData = //Logic to get XAML string from external source
   }
}

Now my View:

Basically I created a hidden TextBlock bound to my XAML String property in the ViewModel and I hooked its Loaded event to an event handler in the code behind of the View:

    private void tb_XamlString_Loaded(object sender, RoutedEventArgs routedEventArgs)
    {
        //First get the ViewModel from DataContext
        MyViewModel vm = content.DataContext as MyViewModel;
        FrameworkElement rootObject = XamlReader.Parse(vm.XamlViewData) as FrameworkElement;
        //Add the XAML portion to the Grid content to render the XAML form dynamically!
        content.Children.Add(rootObject);
    }

This may not be the most elegant but gets the job done. Like some people say, in MVVM there are some cases like this where little code-behind code is needed. It doesn't hurt and also part of this solution still uses the V-VM Binding principles when using the VM to retrieve and populate the XamlString property and exposing it to the View. If we would like to Unit Test the XAML parsing and loading functionality we could delegate it to a separate class.

I hope someone finds this useful!