title: How to use QRegExp
body: <p>The following piece is not working properly:</p>
  
  <pre><code>  QRegExp exp ("[À-Ÿà-ÿA-Za-z0-9\\-\\_]+");
    if (!formatedName.contains(exp)) {
      success = false;
    }
  </code></pre>
  
  <p>This block of code is to validate input strings entered by users.  It should only accept numbers, french and english characters, dash and underscore.</p>
  
  <p>Actually, the code is almost working.  The only problem is that is accept special characters if I enter also legal characters.  So, the string "!@#@" will returns false, but string "hell!@^ooo" will return true.</p>
  
  <p>How should I use regex properly to only accept my regular expression?</p>
  
  <p>thank you</p>