The validation is an event so you must add the event to your code and "add" the event to you event handlers. You must have a function in your code to handle the event for the event to run. Your event can simply call the base event handler.
You can add any event two differnet ways
1) Add the event handler in your code using a "+=" event handler
2) Let Visual Studio automatically add the event handler to your project by cliciking on the object (like Datepicker) and right click the mouse. Then select properties and on the properties window select the lightning bolt. The find the Validate
Event and select the function in your code that handlers the event.
If the event isn't running then it may be calling the wrong function or the event handler was added incorrectly. I normally delete the existing event and then reenter the event. To find all the event handlers in the project, I normally search
the entire project for the characters "+=".
jdweng