title: restricting character set in a Textinput field
body: <p>I have a TextInput field that should be restricted to either capital letters, lowercase letters, numbers and underscores. This is the code I'm trying to use to restrict characters:</p>
  
  <pre><code>restrict="\\A-Z\\a-z\\0-9\\ \\_\\-"
  </code></pre>
  
  <p>I'm using MXML for this Textinput component.</p>
  
  <p>Unfortunately this does not restrict the \ character, which is the last character I'd like to restrict.</p>
  
  <p>How can I add the backslash to the list of restricted characters?</p>
  
  <p>Thanks</p>
  
  <p>Stephen</p>