title: Deny Switching to Tabpage in a tabcontrol
body: <p>I have a form(C#) with a tab control and its has around five tab pages.</p>
  
  <p>each of the tab have a few textboxes. </p>
  
  <p>1) if a User is in say Tab A and edits certain fields i need to validate the text enetered 
  if found invalid then i should not allow any tab switch ? is that possible? </p>
  
  <p>2) Another case could be ... user edits some values and clicks on another tab, on doing so i need to check if the values that were enetered for Tab A is correct or not ? can i do this? </p>
  
  <p>I am a novice to C#... so may be these questions sound very basic any help will be appreciated. </p>
  
  <p>also i want to know what are these events 
  of a tab page </p>
  
  <p>Leave, validated or validating ? </p>