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ServerValidateEventHandler Delegate

Represents the method that will handle the ServerValidate event of a CustomValidator control.

Namespace: System.Web.UI.WebControls
Assembly: System.Web (in system.web.dll)

public delegate void ServerValidateEventHandler (
	Object source,
	ServerValidateEventArgs args
)
/** @delegate */
public delegate void ServerValidateEventHandler (
	Object source, 
	ServerValidateEventArgs args
)
JScript supports the use of delegates, but not the declaration of new ones.

Parameters

source

The source of the event.

args

A ServerValidateEventArgs that contains the event data.

Use this delegate to provide custom code that performs validation on the server. Your code needs to validate the Value property of the args parameter passed to the delegate. Store the result of the validation in the IsValid property of the args parameter.

When you create a ServerValidateEventHandler delegate, you identify the method that will handle the event. To associate the event with your event handler, add an instance of the delegate to the event. The event handler is called whenever the event occurs, unless you remove the delegate. For more information about event handler delegates, see Events and Delegates.

For more information about handling events, see Consuming Events.

The following example demonstrates how to specify and code a handler for a server-side CustomValidator. It displays whether a number entered into a text box is odd or even.


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

<html>
<head>

   <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 runat="server">
  
      <h3>CustomValidator ServerValidate Example</h3>

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

      <p>

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

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

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

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



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

<html>
<head>

   <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;

         }

      }

      void Page_Load(object sender, EventArgs e)
      {

         // Manually register the event-handling method for the  
         // ServerValidate event of the CustomValidator control.
         CustomValidator1.ServerValidate += 
             new ServerValidateEventHandler(this.ServerValidation);

      }

   </script>    

</head>
<body>

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

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

      <p>

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

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

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

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


Windows 98, Windows 2000 SP4, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0
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