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CustomValidator.ServerValidate Event

  • Reference

Definition

Namespace:
System.Web.UI.WebControls
Assembly:
System.Web.dll

Occurs when validation is performed on the server.

public event System.Web.UI.WebControls.ServerValidateEventHandler ServerValidate;

Event Type

ServerValidateEventHandler

Examples

The following code example demonstrates how to specify and code a handler for a server-side CustomValidator control. It creates a custom validation routine, validates the value of a TextBox control for an even number, and then displays the result of the validation.

Important

This example has a text box that accepts user input, which is a potential security threat. By default, ASP.NET Web pages validate that user input does not include script or HTML elements. For more information, see Script Exploits Overview.


<%@ Page Language="C#" AutoEventWireup="True" %>

<!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>
    <title>CustomValidator ServerValidate Example</title>
<script runat="server">

      void ValidateBtn_OnClick(object sender, EventArgs e) 
      { 

         // Display whether the page passed validation.
         if (Page.IsValid) 
         {

            Message.Text = "Page is valid.";

         }

         else 
         {

            Message.Text = "Page is not valid!";

         }

      }

      void ServerValidation(object source, ServerValidateEventArgs args)
      {

         try 
         {

            // Test whether the value entered into the text box is even.
            int i = int.Parse(args.Value);
            args.IsValid = ((i%2) == 0);

         }

         catch(Exception ex)
         {

            args.IsValid = false;

         }

      }

   </script>    

</head>
<body>

   <form id="form1" runat="server">
  
      <h3>CustomValidator ServerValidate Example</h3>

      <asp:Label id="Message"  
           Text="Enter an even number:" 
           Font-Names="Verdana" 
           Font-Size="10pt" 
           runat="server"
           AssociatedControlID="Text1"/>

      <br />

      <asp:TextBox id="Text1" 
           runat="server" />
    
        

      <asp:CustomValidator id="CustomValidator1"
           ControlToValidate="Text1"
           Display="Static"
           ErrorMessage="Not an even number!"
           ForeColor="green"
           Font-Names="verdana" 
           Font-Size="10pt"
           OnServerValidate="ServerValidation"
           runat="server"/>

      <br />
 
      <asp:Button id="Button1"
           Text="Validate" 
           OnClick="ValidateBtn_OnClick" 
           runat="server"/>

   </form>
  
</body>
</html>

Remarks

The ServerValidate event is raised when validation is performed on the server. This event is used to provide a custom validation routine for an input control, such as a TextBox control.

For more information about handling events, see Handling and Raising Events.

Applies to

Product Versions
.NET Framework 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1

See also