CheckBox Class
Assembly: System.Web (in system.web.dll)
[ControlValuePropertyAttribute("Checked")] public class CheckBox : WebControl, IPostBackDataHandler, ICheckBoxControl
/** @attribute ControlValuePropertyAttribute("Checked") */
public class CheckBox extends WebControl implements IPostBackDataHandler, ICheckBoxControl
ControlValuePropertyAttribute("Checked") public class CheckBox extends WebControl implements IPostBackDataHandler, ICheckBoxControl
Not applicable.
Use the CheckBox control to allow the user to select a true or false state.
If you plan to use multiple CheckBox controls, the CheckBoxList control is an alternative control that provides convenient data binding capabilities. However, individual CheckBox controls provide greater control over layout.
Security Note: |
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| A CheckBox control accepts user input, which is a potential security threat. By default, ASP.NET mobile Web pages validate that user input does not include script or HTML elements. For more information, see Script Exploits Overview (Visual Studio). |
Accessibility
The markup rendered by default for this control might not conform to accessibility standards such as the Web Content Accessibility Guidelines 1.0 (WCAG) priority 1 guidelines. For details about accessibility support for this control, see ASP.NET Controls and Accessibility.
The following example demonstrates how to use a CheckBox control to indicate whether tax is included in the calculation for a sales total.
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| The following code sample uses the single-file code model and may not work correctly if copied directly into a code-behind file. This code sample must be copied into an empty text file that has an .aspx extension. For more information on the Web Forms code model, see ASP.NET Web Page Code Model. |
<%@ Page Language="C#" 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"> void Check_Clicked(Object sender, EventArgs e) { // 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"); } void Page_Load(Object sender, EventArgs e) { // Display the subtotal without tax when the page is first loaded. if(!IsPostBack) { // Calculate the subtotal and display the result in currency format. Message.Text = CalculateTotal(false).ToString("c"); } } double CalculateTotal(bool Taxable) { // Calculate the subtotal for the example. double Result = 1.99 + 2.99 + 3.99; // Add tax, if applicable. if(Taxable) { Result += Result * 0.086; } return Result; } </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>
- AspNetHostingPermission for operating in a hosted environment. Demand value: LinkDemand. Permission value: Minimal.
- AspNetHostingPermission for operating in a hosted environment. Demand value: InheritanceDemand. Permission value: Minimal.
System.Web.UI.Control
System.Web.UI.WebControls.WebControl
System.Web.UI.WebControls.CheckBox
System.Web.UI.WebControls.RadioButton
Security Note: