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HtmlInputCheckBox.OnServerChange Method

Raises the ServerChange event. This method allows you to handle the event directly.

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

protected virtual void OnServerChange (
	EventArgs e
)
protected void OnServerChange (
	EventArgs e
)
protected function OnServerChange (
	e : EventArgs
)

Parameters

e

A System.EventArgs that contains event information.

This event is raised when the Web page is submitted to the server and the HtmlInputCheckBox control changes state from the previous post. This method allows you to override the base implementation and provide a custom handler for the event.

NoteNote

The control must have view state enabled for the ServerChange event to work correctly.

Raising an event invokes the event handler through a delegate. For more information, see Raising an Event.

The OnServerChange method also allows derived classes to handle the event without attaching a delegate. This is the preferred technique for handling the event in a derived class.

Notes to Inheritors When overriding OnServerChange in a derived class, be sure to call the base class's OnServerChange method so that registered delegates receive the event.

The following code example demonstrates how to specify and code a handler for the ServerChange event.

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

<html>
<head>

   <script language="C#" runat="server">

      void Button1_Click(object sender, EventArgs e) 
      { 

         if (Prev_Check_State.InnerHtml == Check1.Checked.ToString())
            Span2.InnerHtml = "CheckBox1 did not change state between clicks.";

         if (Check1.Checked == true)
         {          
            Span1.InnerHtml = "CheckBox1 is selected!";
            Prev_Check_State.InnerHtml="True";
         }         
         else
         { 
            Span1.InnerHtml = "CheckBox1 is not selected!";
            Prev_Check_State.InnerHtml="False";
         }
         
      }

      void Server_Changed(object sender, EventArgs e) 
      {
         Span2.InnerHtml = "CheckBox1 changed state between clicks.";
      }

   </script>

</head>

<body>

   <h3>HtmlInputCheckBox Sample</h3>

   <form runat=server>

      <input id="Check1" 
             type="checkbox"
             OnServerChange="Server_Changed" 
             runat="server"/> 
 
      CheckBox1 &nbsp;&nbsp;

      <span id="Span1" 
            style="color:red" 
            runat="server"/>

      <p>

      <input type="button" 
             id="Button1" 
             value="Enter" 
             OnServerClick="Button1_Click" 
             runat="server"/>
      
      <br><br>

      <span id="Span2" 
            runat="server"/>

      <htmlinputhidden id="Prev_Check_State"
                       Visible="false"
                       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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