DataTrigger where value is NOT null?

Question

I know that I can make a setter that checks to see if a value is NULL and do something. Example:

Answer 1

My solution is in the DataContext instance (or ViewModel if using MVVM). I add a property that returns true if the Not Null condition I want is met.

    Public ReadOnly Property IsSomeFieldNull() As Boolean
        Get
            Return If(SomeField is Null, True, False)
        End Get
    End Property

and bind the DataTrigger to the above property. Note: In VB.NET be sure to use the operator If and NOT the IIf function, which doesn't work with Null objects. Then the XAML is: