title: Sensing a decimal in a textBox
body: <p>I'm developing a kind of calculator for the Windows Phone.
  <p>It doesn't need to use decimals. (who needs .39 of a brick)
  <p>How would I detect that there is a decimal in a string or a textBox?</p>
  
  <p><p>EDIT: Thanks, @Bala R and @Afnan. But what I was after was something that filtered out letters as well. My answer's below.</p>