title: RegularExpressionValidator error message
body: <p>I'm trying to add a check for file types to a file upload form:</p>
  
  <pre><code>&lt;asp:FileUpload ID="FileUpload1" runat="server" /&gt;
  &lt;asp:RegularExpressionValidator id="FileUpLoadValidator" runat="server" ErrorMessage="Upload .doc, .pdf or .xls files only." ValidationExpression="^(([a-zA-Z]:)|(\\{2}\w+)\$?)(\\(\w[\w].*))(.xls|.XLS|.pdf|.PDF|.doc|.DOC)$" ControlToValidate="FileUpload1"&gt; &lt;/asp:RegularExpressionValidator&gt;
  </code></pre>
  
  <p>Before adding the <code>RegularExpressionValidator</code> any file type could be uploaded.</p>
  
  <p>After adding it, any file type can still be uploaded.</p>
  
  <p>Can anyone tell me what I'm missing?</p>