ICheckBoxControl.CheckedChanged Event
.NET Framework (current version)
Occurs when the value of the Checked property changes between posts to the server.
Assembly: System.Web (in System.Web.dll)
The CheckedChanged event is raised when the value of Checked changes between posts to the server.
CheckBox implements ICheckBoxControl. The following code example demonstrates how to read the value of the Checked property and respond to a CheckedChanged 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 runat="server"> <title>CheckBox CheckedChanged Example</title> <script runat="server"> Sub Check_Clicked(sender As Object, e As EventArgs) ' Calculate the subtotal and display the result in currency format. ' Include tax if the check box is selected. Message.Text = CalculateTotal(checkbox1.Checked).ToString("c") End Sub Sub Page_Load(sender As Object, e As EventArgs) ' Display the subtotal without tax when the page is first loaded. If Not IsPostBack Then ' Calculate the subtotal and display the result in currency format. Message.Text = CalculateTotal(false).ToString("c") End If End Sub Function CalculateTotal(Taxable As Boolean) As Double ' Calculate the subtotal for the example. Dim Result As Double = 1.99 + 2.99 + 3.99 ' Add tax, if applicable. If(Taxable) Result += Result * 0.086 End If Return Result End Function </script> </head> <body> <form id="form1" runat="server"> <h3>CheckBox CheckedChanged Example</h3> Select whether to include tax in the subtotal. <br /><br /> <table border="1" cellpadding="5"> <tr> <th colspan="2"> Shopping cart </th> </tr> <tr> <td> Item 1 </td> <td> $1.99 </td> </tr> <tr> <td> Item 2 </td> <td> $2.99 </td> </tr> <tr> <td> Item 3 </td> <td> $3.99 </td> </tr> <tr> <td> <b>Subtotal</b> </td> <td> <asp:Label id="Message" runat="server"/> </td> </tr> <tr> <td colspan="2"> <asp:CheckBox id="checkbox1" runat="server" AutoPostBack="True" Text="Include 8.6% sales tax" TextAlign="Right" OnCheckedChanged="Check_Clicked"/> </td> </tr> </table> </form> </body> </html>
.NET Framework
Available since 2.0
Available since 2.0
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