title: How to force a numeric textbox control not to accept empty string?
body: <p>I have a winform app.</p>
  
  <p>I am using a numeric textbox control.
  My problem is that I can erase the value and leave the control.
  When I do that - the value that was before I delete it is the value of the control,
  but the display is an empty value.
  It is important to mention - The default value of the controls is 0.
  I would like that if the user deletes the value of the control , I would like to set the value of the control to 0.</p>
  
  <p>My question is : </p>
  
  <p>How can I force a numeric textbox control not to display an empty value ??</p>
  
  <p>Thanks .</p>