title: Cancelling ListBox SelectedIndexChange Event
body: <p>Is it possible to cancel the SelectedIndexChange event for a listbox on a winforms application?  This seems like such a logical thing to have that I must be overlooking some easy feature.  Basically, I have been popping up a message box asking if the user really wants to move to another item, as this will change the UI and I don't want their changes to be lost.  I'd like to be able to cancel the event in case the user has not saved what they are working on.  Is there a better way of doing this?</p>