RegularExpressionValidator Example in ASP.NET using C#

In this article we will introduce with the RegularExpressionValidator control in ASP.NET using C#.

RegularExpressionValidator Example in ASP.NET using C#

RegularExpressionValidator control in ASP.NET is used to check the user input based on a pattern that you define using RegularExpression. If the value is not match with the RegularExpression then the error message will be displayed. You can set the ErrorMessage property which you want to display. The another property is ControlToValidate in which you can set the attached control instance. In this example we use the Email address RegularExpression.
The following image shows how can I edit ValidationExpression.

RegularExpressionValidator.aspx (Design Page):

RegularExpressionValidator.aspx (source code):

<%@ Page Title="" Language="C#" MasterPageFile="~/RoseindiaMaster.master" AutoEventWireup="true"
CodeFile="RegularExpressionValidator.aspx.cs" Inherits="RegularExpressionValidator" %>
<asp:Content ID="Content1" ContentPlaceHolderID="head" runat="Server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="Server">
<div>
<h2 style="color: Green">
RegularExpressionValidator in ASP.NET 4 , C#</h2>
<strong>Email-id:</strong>
<br />
<asp:TextBox ID="emailidTextBox" runat="server" Width="193px" 
Font-Names="Verdana" />
&nbsp;&nbsp;&nbsp;&nbsp;
<asp:Button ID="submitButton" runat="server" Text="Submit" Width="76px" />
<br />
<asp:Label runat="server" Text="Example: suraj@gmail.com" ForeColor="Gray" /> 
<br />
<asp:RegularExpressionValidator ID="RegularExpressionValidator1" runat="server" 
ErrorMessage="You must enter an email address" 
ControlToValidate="emailidTextBox" ForeColor="Red" 
ValidationExpression="\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*">
</asp:RegularExpressionValidator>
</div>
</asp:Content>

Output: