how can I add a double click event to a control that doesn't have a double click event =P
like a combo box!!!
<sarcasm>Use more exclamation points - that usually gets the job done!</sarcasm>
But, seriously, you can't. Try checking for the simple "Click" event and then see if the time between two successive clicks is small enough. I'm not sure where you can find the system double-click timing though. Try googling for that.
However, I would seriously think twice about adding such non-standard behavior to a standard control. Users normally don't expect this so they will quite likely be unhappy about this. Remember - the best UI is the one that offers the user least surprises. Better think of another way to do what you are trying to do.