WithEvents Addendum

(Follows on from yesterday's post.)

Because WithEvents fields are wrapped in a property, passing them by reference is should be a problem, but it magically seems to work! This is an example of VB.NET continuing in its fine tradition of "protecting" the developer from messy details.

Reflector reveals that if you write this:

Friend WithEvents Button1 As System.Windows.Forms.Button

 

Private Sub X()

    Y(Button1)

End Sub

 

Private Sub Y(ByRef a As Button)

End Sub

the VB compiler generates code for X() like this:

Private Sub X()

    Dim button1 As Button = Me.Button1

    Me.Y(button1)

    Me.Button1 = button1

End Sub