C# NSubstitude react to unsubsribe from event (operator -=)

Question

I am trying to throw exception when unsubscribing from event.

.NET Framework 4.8

I tried this:

var sFE = NSubstitute.Substitute.For<System.Windows.FrameworkElement>();
sFE.When(x => x.SizeChanged -= Arg.Any<System.Windows.SizeChangedEventHandler>())
    .Do(x =>
{
    throw new System.MissingMethodException();
});

But I get error: System.ArgumentNullException: 'Value cannot be null. Parameter name: handler'

Please can you help me?

Answer 1

等待大神答复