title: How do you validate phone number in asp.net?
body: <p>I need to validate phone number that allows numeric and symbols + - () 
  how can i do so in asp.net?</p>
  
  <pre><code>&lt;asp:TextBox ID="TxtNo" runat="server"&gt;&lt;/asp:TextBox&gt;
      &lt;asp:RegularExpressionValidator ID="RegularExpressionValidator2" runat="server" ErrorMessage="Enter valid Phone number" ControlToValidate="TxtNo" &gt;&lt;/asp:RegularExpressionValidator&gt;
  </code></pre>