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HtmlInputRadioButton.ServerChange Event

Occurs when the value of the Checked property of the HtmlInputRadioButton control changes between posts to the server.

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

public event EventHandler ServerChange
/** @event */
public void add_ServerChange (EventHandler value)

/** @event */
public void remove_ServerChange (EventHandler value)

JScript supports the use of events, but not the declaration of new ones.

The ServerChange event is raised when the Checked property of the HtmlInputRadioButton control changes value between posts to the server. This allows you to create a custom event handler that performs a specific set of instructions (such as data validation) when the event is raised.

NoteNote

The control must have view state enabled for the ServerChange event to work correctly. To enable view state for all controls on the Web Forms page, set the Page.EnableViewState property to true. You can also enable view state for an individual control by setting the Control.EnableViewState property to true.

For more information about handling events, see Consuming Events.

The following code example demonstrates how to specify and code a handler for the ServerChange event. The custom event handler updates a label on the Web page to display the value of the selected radio button.

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

<html>
<head>

   <script runat="server">

      void Server_Change(object sender, EventArgs e) 
      {
         if (Radio1.Checked)
            Span1.InnerHtml = "You selected " +
                              Radio1.Value;
         else if (Radio2.Checked)
            Span1.InnerHtml = "You selected " +
                              Radio2.Value;
         else if (Radio3.Checked)
            Span1.InnerHtml = "You selected " +
                              Radio3.Value;
      }
         

   </script>

</head>

<body>

   <form runat="server">

      <h3>HtmlInputRadioButton Sample</h3>

      <input type="radio" 
             id="Radio1" 
             name="Mode"
             value="Radio Button 1"
             OnServerChange="Server_Change" 
             runat="server"/>
      Option 1
      <br>

      <input type="radio" 
             id="Radio2" 
             name="Mode"
             value="Radio Button 2"
             OnServerChange="Server_Change" 
             runat="server"/>
      Option 2
      <br>

      <input type="radio" 
             id="Radio3" 
             name="Mode"
             value="Radio Button 3"
             OnServerChange="Server_Change" 
             runat="server"/>
      Option 3

      <p>

      <input type="submit" 
             id="Button1" 
             value="Submit" 
             runat="server"/>

      <p>

      <span id="Span1" 
            runat="server" />

   </form>

</body>
</html>


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

<html>
<head>

   <script runat="server">

      void Server_Change(object sender, EventArgs e) 
      {
         if (Radio1.Checked)
         {
            Span1.InnerHtml = "You selected " + Radio1.Value;
         }
         else if (Radio2.Checked)
         {
            Span1.InnerHtml = "You selected " + Radio2.Value;
         }
         else if (Radio3.Checked)
         {
            Span1.InnerHtml = "You selected " + Radio3.Value;
         }
      }

      void Page_Load(object sender, EventArgs e)
      {
         // Create an EventHandler delegate for the method you want to
         // handle the event, and then add it to the list of methods
         // called when the event is raised.
         Radio1.ServerChange += new System.EventHandler(this.Server_Change);
         Radio2.ServerChange += new System.EventHandler(this.Server_Change);
         Radio3.ServerChange += new System.EventHandler(this.Server_Change);
      }         

   </script>

</head>

<body>

   <form runat="server">

      <h3>HtmlInputRadioButton ServerChange Example</h3>

      <input type="radio" 
             id="Radio1" 
             name="Mode"
             value="Radio Button 1"
             runat="server"/>
      Option 1
      <br>

      <input type="radio" 
             id="Radio2" 
             name="Mode"
             value="Radio Button 2"
             runat="server"/>
      Option 2
      <br>

      <input type="radio" 
             id="Radio3" 
             name="Mode"
             value="Radio Button 3"
             runat="server"/>
      Option 3

      <p>

      <input type="submit" 
             id="Button1" 
             value="Submit" 
             runat="server"/>

      <p>

      <span id="Span1" 
            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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