Unit testing broken?

[jg-at-home]

I'm trying to use nodify in a project and want to Unit Test my ViewModel (that's one of the points of MVVM, yes?!)

public class MyViewModel : ObservableObject
{
   // etc
}

But when I try to create an instance in my test project, it crashes due to a null reference in this:

    public class ObservableObject : INotifyPropertyChanged
    {
        /// <summary>
        /// Gets or sets the dispatcher to use to dispatch PropertyChanged events. Defaults to UI thread.
        /// </summary>
        public virtual Action<Action> PropertyChangedDispatcher { get; set; } = Application.Current.Dispatcher.Invoke;

Is there a work-around? (I could subclass my VM again to override the dispatcher but that makes me uncomfortable and might not even work).

[miroiu]

You can remove the PropertyChangedDispatcher and call the PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName)) directly. Or try something like this:

 public class ObservableObject : INotifyPropertyChanged
 {
     /// <summary>
     /// Gets or sets the dispatcher to use to dispatch PropertyChanged events. Defaults to UI thread.
     /// </summary>
     public virtual Action<Action> PropertyChangedDispatcher { get; set; }

     /// <summary>
     /// Occurs when a property value changes
     /// </summary>
     public event PropertyChangedEventHandler? PropertyChanged;

     public ObservableObject()
     {
         if (Application.Current != null)
         {
             PropertyChangedDispatcher = Application.Current.Dispatcher.Invoke;
         }
         else
         {
             PropertyChangedDispatcher = (Action action) => action();
         }
     }

[jg-at-home]

Thanks!