IPostBackEventHandler Interface

Defines the method ASP.NET server controls must implement to handle postback events.

Namespace:   System.Web.UI
Assembly:  System.Web (in System.Web.dll)

public interface IPostBackEventHandler
public interface class IPostBackEventHandler
type IPostBackEventHandler = interface end
Public Interface IPostBackEventHandler
System_CAPS_pubmethod RaisePostBackEvent

When implemented by a class, enables a server control to process an event raised when a form is posted to the server.


To create a server control that captures form submission information from the browser, you must implement this interface. For more information on how to use this interface, see Server Event Handling in ASP.NET Web Forms Pages.


The following code example defines a custom button server control that causes postback, captures the postback event using the RaisePostBackEvent method, and raises a Click event on the server.

using System;
using System.Web.UI;
using System.Collections;
using System.Collections.Specialized;

namespace CustomControls {

   [System.Security.Permissions.PermissionSet(System.Security.Permissions.SecurityAction.Demand, Name="FullTrust")]   
   public class MyButton: Control, IPostBackEventHandler {

      // Defines the Click event.
      public event EventHandler Click;

      //Invoke delegates registered with the Click event.
      protected virtual void OnClick(EventArgs e) {

         if (Click != null) {
            Click(this, e);

      // Define the method of IPostBackEventHandler that raises change events.
      public void RaisePostBackEvent(string eventArgument){

         OnClick(new EventArgs());

      protected override void Render(HtmlTextWriter output) {
         output.Write("<INPUT TYPE = submit name = " + this.UniqueID + 
            " Value = 'Click Me' />");   
Imports System
Imports System.Web.UI
Imports System.Collections
Imports System.Collections.Specialized

Namespace CustomControls    

    <System.Security.Permissions.PermissionSetAttribute(System.Security.Permissions.SecurityAction.Demand, Name:="FullTrust")> Public Class MyButton
        Inherits Control
        Implements IPostBackEventHandler

        ' Define the Click event.
        Public Event Click As EventHandler

        ' Invoke delegates registered with the Click event.
        Protected Overridable Sub OnClick(e As EventArgs)            
            RaiseEvent Click(Me, e)
        End Sub

        ' Define the method of IPostBackEventHandler that raises change events.
        Public Sub RaisePostBackEvent(eventArgument As String) _
        Implements IPostBackEventHandler.RaisePostBackEvent

            OnClick(New EventArgs())
        End Sub       

        Protected Overrides Sub Render(output As HtmlTextWriter)
            output.Write("<INPUT TYPE = submit name = " & Me.UniqueID & _
                " Value = 'Click Me' />")
        End Sub

    End Class
End Namespace
Version Information
.NET Framework
Available since 1.1
Return to top