title: Regular Expression for a Vehicle Number Textbox
body: <p>I have a textbox in asp.net detailsview.
  This textbox can only take vehicle number like:</p>
  
  <p>ABG-999 <br />
  ATG-9090 <br />
  AB-122<br />
  B-9999<br />
  J-111<br />
  880099<br />
  88221<br /></p>
  
  <p>Can somebody produce a Regular Expression that i can apply on the textbox? I want the use to only add "-" sign and nothing like a space or a full stop should be allowed.</p>
  
  <p><strong>EDIT-1</strong></p>
  
  <pre><code>&lt;asp:TextBox ID="TextBox1" runat="server" Text='&lt;%# Bind("bowzer_no") %&gt;' ControlToValidate="TextBox1" /&gt;
  &lt;asp:RegularExpressionValidator ControlToValidate = "TextBox1" ID="RegularExpressionValidator1" runat="server" ErrorMessage="Invalid" &gt;&lt;/asp:RegularExpressionValidator&gt;
  </code></pre>
  
  <p>I don't know what to type in the ValidationExpression to achieve my goal.</p>