CheckBox Class (System.Web.UI.WebControls)

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This page is specific to

Microsoft Visual Studio 2008/.NET Framework 3.5

Other versions are also available for the following:

.NET Framework Class Library

CheckBox Class

Updated: November 2007

Displays a check box that allows the user to select a true or false condition.

Namespace: System.Web.UI.WebControls
Assembly: System.Web (in System.Web.dll)

Syntax

Visual Basic (Declaration)

<ControlValuePropertyAttribute("Checked")> _
<AspNetHostingPermissionAttribute(SecurityAction.LinkDemand, Level := AspNetHostingPermissionLevel.Minimal)> _
<AspNetHostingPermissionAttribute(SecurityAction.InheritanceDemand, Level := AspNetHostingPermissionLevel.Minimal)> _
Public Class CheckBox _
    Inherits WebControl _
    Implements IPostBackDataHandler, ICheckBoxControl

Visual Basic (Usage)

Dim instance As CheckBox

[ControlValuePropertyAttribute("Checked")]
[AspNetHostingPermissionAttribute(SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
[AspNetHostingPermissionAttribute(SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal)]
public class CheckBox : WebControl, IPostBackDataHandler, 
    ICheckBoxControl

Visual C++

[ControlValuePropertyAttribute(L"Checked")]
[AspNetHostingPermissionAttribute(SecurityAction::LinkDemand, Level = AspNetHostingPermissionLevel::Minimal)]
[AspNetHostingPermissionAttribute(SecurityAction::InheritanceDemand, Level = AspNetHostingPermissionLevel::Minimal)]
public ref class CheckBox : public WebControl, 
    IPostBackDataHandler, ICheckBoxControl

/** @attribute ControlValuePropertyAttribute("Checked") */
/** @attribute AspNetHostingPermissionAttribute(SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal) */
/** @attribute AspNetHostingPermissionAttribute(SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal) */
public class CheckBox extends WebControl implements IPostBackDataHandler, 
    ICheckBoxControl

JScript

public class CheckBox extends WebControl implements IPostBackDataHandler, ICheckBoxControl

ASP.NET

<asp:CheckBox />

Remarks

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:
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.

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.

Topic	Location
How to: Add CheckBox Web Server Controls to a Web Forms Page	Building ASP .NET Web Applications
How to: Add CheckBox Web Server Controls to a Web Forms Page	Building ASP .NET Web Applications
How to: Add CheckBox Web Server Controls to a Web Forms Page	Building ASP .NET Web Applications in Visual Studio
How to: Add CheckBox Web Server Controls to a Web Forms Page (Visual Studio)	Building ASP .NET Web Applications in Visual Studio
How to: Add CheckBoxList Web Server Controls to a Web Forms Page	Building ASP .NET Web Applications
How to: Add CheckBoxList Web Server Controls to a Web Forms Page	Building ASP .NET Web Applications
How to: Customize the ASP.NET CreateUserWizard Control	Building ASP .NET Web Applications
How to: Customize the ASP.NET CreateUserWizard Control	Building ASP .NET Web Applications
How to: Customize the ASP.NET CreateUserWizard Control	Building ASP .NET Web Applications in Visual Studio
How to: Get and Set a CheckBox Web Server Control Value Programmatically	Building ASP .NET Web Applications
How to: Get and Set a CheckBox Web Server Control Value Programmatically	Building ASP .NET Web Applications
How to: Get and Set a CheckBox Web Server Control Value Programmatically	Building ASP .NET Web Applications in Visual Studio
How to: Respond to User Selection in a CheckBox Web Server Control	Building ASP .NET Web Applications
How to: Respond to User Selection in a CheckBox Web Server Control	Building ASP .NET Web Applications
How to: Respond to User Selection in a CheckBox Web Server Control	Building ASP .NET Web Applications in Visual Studio
How to: Set Focus on ASP.NET Web Server Controls	Building ASP .NET Web Applications
How to: Set Focus on ASP.NET Web Server Controls	Building ASP .NET Web Applications
How to: Set Focus on ASP.NET Web Server Controls	Building ASP .NET Web Applications in Visual Studio
Walkthrough: Validating User Input in a Web Forms Page	Building ASP .NET Web Applications in Visual Studio
Walkthrough: Validating User Input in a Web Forms Page	Building Applications with Visual Web Developer

Examples

The following example demonstrates how to use a CheckBox control to indicate whether tax is included in the calculation for a sales total.

Note:
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.

Visual Basic

<%@ 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  >
<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>

<%@ 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  >
<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>

Permissions

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.

Inheritance Hierarchy

System..::.Object
  System.Web.UI..::.Control
    System.Web.UI.WebControls..::.WebControl
      System.Web.UI.WebControls..::.CheckBox
        System.Web.UI.WebControls..::.RadioButton

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Platforms

Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Version Information