title: Numeric Only TextBox
body: <p>I've looked all over the place, but it seems that examples I have seen allow only numbers 0-9</p>
  
  <p>I'm writing a Pythagorean Theorem program. I wish to have the phone (Windows Phone 7) check if there are <strong>ANY</strong> alpha (A-Z, a-z), symbols (@,%), or anything other than a number in the textbox. If not, then it will continue computing. I want to check so there will be no future errors.</p>
  
  <p>This is basically a bad pseudocode of what I want it to do</p>
  
  <p>txtOne-->any alpha?--No-->any symbols--No-->continue...</p>
  
  <p>I would actually prefer a command to check if the string is <strong>completely</strong> a number.</p>
  
  <p>Thanks in advance!</p>