HtmlInputRadioButton.ServerChange Event
Occurs when the value of the Checked property of the HtmlInputRadioButton control changes between posts to the server.
[Visual Basic] Public Event ServerChange As EventHandler [C#] public event EventHandler ServerChange; [C++] public: __event EventHandler* ServerChange;
[JScript] In JScript, you can handle the events defined by a class, but you cannot define your own.
Event Data
The event handler receives an argument of type EventArgs.
Remarks
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.
Note 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.
Example
[Visual Basic, C#] The following 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.
[Visual Basic] <%@ Page Language="VB" AutoEventWireup="True" %> <html> <head> <script runat="server"> Sub Server_Change(sender As Object , e As EventArgs) If Radio1.Checked Then Span1.InnerHtml = "You selected " & _ Radio1.Value ElseIf Radio2.Checked Then Span1.InnerHtml = "You selected " & _ Radio2.Value ElseIf Radio3.Checked Then Span1.InnerHtml = "You selected " & _ Radio3.Value End If End Sub </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> [C#] <%@ 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> [Visual Basic] <%@ Page Language="VB" AutoEventWireup="True" %> <html> <head> <script runat="server"> Sub Server_Change(sender As Object, e As EventArgs) If Radio1.Checked Then Span1.InnerHtml = "You selected " & Radio1.Value ElseIf Radio2.Checked Then Span1.InnerHtml = "You selected " & Radio2.Value ElseIf Radio3.Checked Then Span1.InnerHtml = "You selected " & Radio3.Value End If End Sub Sub Page_Load(sender As Object, e As EventArgs) ' 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. AddHandler Radio1.ServerChange, AddressOf Server_Change AddHandler Radio2.ServerChange, AddressOf Server_Change AddHandler Radio3.ServerChange, AddressOf Server_Change End Sub </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> [C#] <%@ 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>
[C++, JScript] No example is available for C++ or JScript. To view a Visual Basic or C# example, click the Language Filter button
in the upper-left corner of the page.
Requirements
Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family
See Also
HtmlInputRadioButton Class | HtmlInputRadioButton Members | System.Web.UI.HtmlControls Namespace | OnServerChange | System.EventHandler | Checked