title: Regular expression to validate comma separated email addresses?
body: <p>I need to validate email addresses which can be single or several comma-separated ones.</p>
  
  <p>Before I was using in a regular expression validator an expression like:</p>
  
  <pre><code>string exp = @"((\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*)*([,])*)*";
  </code></pre>
  
  <p>and it was validating multiple or one single email address.</p>
  
  <p>But same expression is not valdiating in C#? It says valid to invalid addresses as well.</p>
  
  <p>Please correct me or suggest me an expression to validate email addresse(s).</p>