Use Regular expression to validate a Phone number : Regular Expression « Validation « ASP.NET Tutorial

<html><body>
   <form runat="server">
      <asp:Label id="lblMessage" runat="server" /><br>
      <asp:Panel id="Panel1" runat="server">
         <table>
         <tr>
            <td valign="top">Phone (<i>xxx-xxxx</i>):</td>
            <td valign="top">
               <asp:TextBox id="tbPhone" runat="server"
                  size=11 /><br>
               <asp:RegularExpressionValidator runat="server"
                  ControlToValidate="tbPhone"
                  ValidationExpression="[0-9]{3}-[0-9]{4}"
                  ErrorMessage="That is not a valid phone" />
            </td>
         </tr>


         <tr>
            <td colspan="2" valign="top" align="right">
               <asp:Button id="Submit" runat="server" 
                  text="Add" />
            </td>
         </tr>
         </table>
      </asp:Panel>
   </form>
</body></html>

8.9.Regular Expression
	8.9.1.	The predefined character classes
	8.9.2.	quantifiers used to create patterns that match a variable number of characters at a certain position in the string
	8.9.3.	Metacharacters for Matching Single Characters
	8.9.4.	Metacharacters for Matching Types of Characters
	8.9.5.	Quantifiers
	8.9.6.	Commonly Used Regular Expressions
	8.9.7.	RegularExpressionValidator compares value against a regular expression
	8.9.8.	Regular Expression based validation (C#)
	8.9.9.	Use asp:RegularExpressionValidator to check the zip code
	8.9.10.	Use asp:RegularExpressionValidator to check the email address
	8.9.11.	Use Regular expression to validate a Phone number