Display a messagebox from the ViewModel using Prism’s InteractionRequests

Prism has a nice feature called InteractionRequests. We can use this when the view-model needs to initiate an interaction, like displaying a messagebox.

Below is a simple example:

XAML:

In XAML I define the PopupChildWindowAction to display the dialog to the user.  The visuals of this dialog is defined in the SaveWindowsTemplate.
The magic here is the InteractionRequestTrigger from Prism. I set the SourceObject to the SaveRequest that is defined in the ViewModel.

SaveRequest is a InteractionRequest that define a Raise method, that we can use to raise the event.

I then use a interaction trigger to call the Cancel method in the viewmodel.  See Preview post.

ViewModel:

And the result look like this: