HtmlInputCheckBox.OnServerChange Method (EventArgs)

 

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 Overridable Sub OnServerChange (
	e As EventArgs
)

Parameters

e
Type: System.EventArgs

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.

System_CAPS_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 NIB: 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="VB" 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>HtmlInputCheckBox Sample</title>
<script language="VB" runat="server">

    Sub Button1_Click(sender As Object, e As EventArgs)

        If Prev_Check_State.Value = Check1.Checked.ToString() Then
            Span2.InnerHtml = "CheckBox1 did not change state between clicks."
        End If
        If Check1.Checked = True Then
            Span1.InnerHtml = "CheckBox1 is selected!"
            Prev_Check_State.Value = "True"
        Else
            Span1.InnerHtml = "CheckBox1 is not selected!"
            Prev_Check_State.Value = "False"
        End If
    End Sub 'Button1_Click


    Sub Server_Changed(sender As Object, e As EventArgs)
        Span2.InnerHtml = "CheckBox1 changed state between clicks."
    End Sub 'Server_Changed

  </script>

</head>

<body>

   <h3>HtmlInputCheckBox Sample</h3>

   <form id="form1" runat="server">

      <input id="Check1" 
             type="checkbox"
             onserverchange="Server_Changed" 
             runat="server"/> 

      CheckBox1 &nbsp;&nbsp;

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

      <br />

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

      <br /><br />

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

      <input type="hidden" id="Prev_Check_State"
                       visible="false"
                       runat="server"/>
   </form>

</body>
</html>

.NET Framework
Available since 1.1
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