title: .net Calendar requiredFieldValidator
body: <p>Is it possible to add a requiredFieldValidator to a calendar?
  For example I have a submit button and if it is clicked without selecting a date red text should come up saying please select date first.</p>
  
  <p>I know one way is to simply check for selectedDate in c# code but can I create a requiredFieldValidator as for textboxes?</p>
  
  <p>Thanks in advance.</p>