Catel show dialog window inside a ViewModel

Question

Please Help. I put this construction in any method to main ViewModel

Thread thread = new Thread(() =>
{
     _visualizerService.ShowDialog(new PurchaseWindowViewModel());
});

thread.SetApartmentState(ApartmentState.STA);
thread.Start();

And i have exception in PurchaseWindowViewModel.xaml.cs

An exception of type 'System.InvalidOperationException' occurred in PresentationFramework.dll but was not handled in user code. Additional information: Not access to object Freezable "Catel.Windows.Media.Effects.GrayscaleEffect"

through the threads, as it can not be frozen.

Answer 1

Creating a window on a separate thread is hardly ever required and only "required" in edge-case scenarios. Please update your question why you want to use a window on a non-ui thread if the answer below does not solve your issue.

I recommend that you use this code instead:

await _visualizerService.ShowDialogAsync<PurchaseWindowViewModel>();

or non async:

_visualizerService.ShowDialog<PurchaseWindowViewModel>();