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Listing 3.13 - ShowRegularExpressionValidator.aspx

Illustrates how to use the ASP.NET RegularExpressionValidator control to validate a form field against a regular expression string pattern.

Listing 3.13 - ShowRegularExpressionValidator.aspx (C#)
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<%@ Page Language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
    <title>Show RegularExpressionValidator</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
    
    <asp:Label  
        id="lblEmail"
        Text="Email Address:"
        AssociatedControlID="txtEmail"
        Runat="server" />
    <asp:TextBox
        id="txtEmail"
        Runat="server" />
    <asp:RegularExpressionValidator
        id="regEmail"
        ControlToValidate="txtEmail"
        Text="(Invalid email)"
        ValidationExpression="\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*"
        Runat="server" />    
    
    <br /><br />
    
    <asp:Button
        id="btnSubmit"
        Text="Submit"
        Runat="server" />
    
    </div>
    </form>
</body>
</html>