Hi Roger,
it works fine. Try following demo:
<StackPanel>
<Button x:Name="btn" Content="Click me"/>
</StackPanel>
And CodeBehind:
Public Class Window1
Private Sub Window_Loaded(sender As Object, e As RoutedEventArgs)
AddHandler Me.btn.Click, AddressOf Btn_Click
End Sub
Private Sub Btn_Click(sender As Object, e As RoutedEventArgs)
MessageBox.Show("Click Event")
RemoveHandler Me.btn.Click, AddressOf Btn_Click
End Sub
End Class