title: c# how to check if a text box has one digit?
body: <p>at the moment, my program crashes if only one digit exists inside a textbox. E.g. User puts '6' into a Day textbox (which it should be two digits), and the program will crash when he/she clicks the 'Convert' button. It has to be two digits or else the program crashes...</p>
  
  <p>my application is a time converter, by the way.</p>
  
  <p>thanks in advance :)</p>