Windows Presentation Foundation error

When I try to add the click event to the xaml code: <Button x:Name="cmdCalcUnitPrice" Content="Calculate" HorizontalAlignment="Left" Margin="48,16,0,0" Grid.Row="9" VerticalAlignment="Top" Width="54" Click=" "/> . IntelliSense shows the "New Event handler popup, but when I hit the TAB key, I get the error message "Ensure Event Failed". When I double click the control to try and insert an Event stub in vb code-behind file, I get the error message "Unable to add event handler". Also, if you have controls on a window form, shouldn't you see something in the vb code-behind file?

Thanks