HideDisabledControlAdapter Class (System.Web.UI.WebControls.Adapters)

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Microsoft Visual Studio 2008/.NET Framework 3.5

Other versions are also available for the following:

.NET Framework Class Library

HideDisabledControlAdapter Class

Updated: November 2007

Provides rendering capabilities for the associated Web control to modify the default markup or behavior for a specific browser.

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

Syntax

Visual Basic (Declaration)

<AspNetHostingPermissionAttribute(SecurityAction.InheritanceDemand, Level := AspNetHostingPermissionLevel.Minimal)> _
<AspNetHostingPermissionAttribute(SecurityAction.LinkDemand, Level := AspNetHostingPermissionLevel.Minimal)> _
Public Class HideDisabledControlAdapter _
    Inherits WebControlAdapter

Visual Basic (Usage)

Dim instance As HideDisabledControlAdapter

[AspNetHostingPermissionAttribute(SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal)]
[AspNetHostingPermissionAttribute(SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
public class HideDisabledControlAdapter : WebControlAdapter

Visual C++

[AspNetHostingPermissionAttribute(SecurityAction::InheritanceDemand, Level = AspNetHostingPermissionLevel::Minimal)]
[AspNetHostingPermissionAttribute(SecurityAction::LinkDemand, Level = AspNetHostingPermissionLevel::Minimal)]
public ref class HideDisabledControlAdapter : public WebControlAdapter

/** @attribute AspNetHostingPermissionAttribute(SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal) */
/** @attribute AspNetHostingPermissionAttribute(SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal) */
public class HideDisabledControlAdapter extends WebControlAdapter

JScript

public class HideDisabledControlAdapter extends WebControlAdapter

Remarks

The HideDisabledControlAdapter class adapts the associated WebControl control to modify the default markup or behavior for a specific browser. You can extend the HideDisabledControlAdapter class to further customize rendering of the WebControl control.

Adapters are compiled .NET Framework components that take over one or more stages in the life cycle of a page or control. Extending the HideDisabledControlAdapter class will provide access to the life-cycle stages of the WebControl control. For more information, see Architectural Overview of Adaptive Control Behavior.

The initial request for an adapter causes the .NET Framework to search for a mapped adapter for the control given the characteristics of the requesting browser. Browser definition files are used by the HttpBrowserCapabilities class to identify the characteristics of the client browser and map the adapter to the browser type. For more information, see Architectural Overview of Adaptive Control Behavior.

For a description of the adaptive rendering architecture of ASP.NET and a step-by-step walkthrough that shows how to implement a control adapter and map it to a control, see "Authoring ASP.NET Server Control Adapters: An Introduction" in the MSDN Library at http://msdn.microsoft.com/library.

Examples

The following code example shows how to extend the HideDisabledControlAdapter class to display a Label control in an enabled and disabled state. This example contains three parts:

An adapter derived from the HideDisabledControlAdapter class.
The .aspx file that incorporates the Label control and device-specific content.
A browser file to link the adapter to a device type.

The following code example demonstrates how to extend the HideDisabledControlAdapter class.

Visual Basic

Imports System
Imports System.Web
Imports System.Web.UI
Imports System.Security.Permissions

Namespace Contoso
    <AspNetHostingPermission( _
        SecurityAction.Demand, _
        Level:=AspNetHostingPermissionLevel.Minimal)> _
    <AspNetHostingPermission( _
        SecurityAction.InheritanceDemand, _
        Level:=AspNetHostingPermissionLevel.Minimal)> _
    Public Class HideDisabledControlContosoAdapter
        Inherits System.Web.UI.WebControls.Adapters.HideDisabledControlAdapter

        Protected Overloads ReadOnly Property Control() As _
            System.Web.UI.WebControls.Label
            Get
                Return CType( _
                    MyBase.Control, _
                    System.Web.UI.WebControls.Label)
            End Get
        End Property

        ' Do not render the control if Enabled is false.
        Protected Overrides Sub Render(ByVal writer As HtmlTextWriter)
            If (Control.ID.StartsWith("Contoso")) Then
                If (Not Control.Enabled) Then
                    Return
                End If
            End If

            MyBase.Render(writer)
        End Sub
    End Class
End Namespace

using System;
using System.Web;
using System.Web.UI;
using System.Security.Permissions;

namespace Contoso
{
    [AspNetHostingPermission(
        SecurityAction.Demand, 
        Level = AspNetHostingPermissionLevel.Minimal)]
    [AspNetHostingPermission(
        SecurityAction.InheritanceDemand, 
        Level = AspNetHostingPermissionLevel.Minimal)]
    public class HideDisabledControlContosoAdapter:
        System.Web.UI.WebControls.Adapters.HideDisabledControlAdapter
    {
        // Link the Label control to the adapter.
        protected new System.Web.UI.WebControls.Label Control
        {
            get
            {
                return (System.Web.UI.WebControls.Label)base.Control;
            }
        }

        // Do not render the Contoso controls if Enabled is false.
        protected override void Render(System.Web.UI.HtmlTextWriter writer)
        {
            if (Control.ID.StartsWith("Contoso"))
            {
                if (!Control.Enabled)
                {
                    return;
                }
            }

            base.Render(writer);
        }
    }
}

The following code example demonstrates how to declare a Label control with device-specific content.

Visual Basic

<%@ page language="VB" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html  >
<head id="Head1" runat="server">
    <title>HideDisabledControl Adapter</title>
    <script runat="server">
        Sub ServerButtonClick(ByVal source As Object, ByVal args As EventArgs)
            If (Button1.Text.Equals("Enable Label")) Then
                ContosoLabel1.Enabled = True
                Button1.Text = "Disable Label"
                messageLabel.Text = "The label is <b>En</b>abled"
            Else
                ContosoLabel1.Enabled = False
                Button1.Text = "Enable Label"
                messageLabel.Text = "The label is <b>dis</b>abled"
            End If
        End Sub
    </script>
</head>
<body style="background-color:silver">
    <form id="Form1" runat="server">
        <asp:Label id="ContosoLabel1"             
            text="Contoso Label" 
            WinCE:text="CE Label"
            BorderWidth="3" 
            BorderStyle="Inset"
            style="FONT-SIZE: xx-small"
            runat="server">
            </asp:Label>
        <br />
        <asp:Button id="Button1" 
            text="Disable Label"
            OnClick="ServerButtonClick" 
            runat="server" />
        <br />    
        <asp:Label id="messageLabel" 
            runat="server" 
            style="FONT-SIZE: xx-small"
            AssociatedControlID="Button1">
            <i>Select the button to disable the label.</i>
        </asp:Label>
    </form>
</body>
</html>

<%@ page language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html  >
<head id="Head1" runat="server">
    <title>HideDisabledControl Adapter</title>
    <script runat="server">
        void ServerButtonClick(Object source, EventArgs args)
        {
            if (Button1.Text == "Enable Label")
            {
                ContosoLabel1.Enabled = true;
                Button1.Text = "Disable Label";
                messageLabel.Text = "The label is <b>En</b>abled";
            }
            else
            {
                ContosoLabel1.Enabled = false;
                Button1.Text = "Enable Label";
                messageLabel.Text = "The label is <b>dis</b>abled";
            }
        }
    </script>
</head>
<body style="background-color:silver">
    <form id="Form1" runat="server">
        <asp:Label id="ContosoLabel1"             
            text="Contoso Label" 
            WinCE:text="CE Label"
            BorderWidth="3" 
            BorderStyle="Inset"
            style="FONT-SIZE: xx-small"
            runat="server">
            </asp:Label>
        <br />
        <asp:Button id="Button1" 
            text="Disable Label"
            OnClick="ServerButtonClick" 
            runat="server" />
        <br />    
        <asp:Label id="messageLabel" 
            runat="server" 
            style="FONT-SIZE: xx-small"
            AssociatedControlID="Button1">
            <i>Select the button to disable the label.</i>
        </asp:Label>
    </form>
</body>
</html>

The following code example shows how to link the Label control to the custom adapter for browsers running on Windows CE .NET.

<browsers>
    <browser refID="WinCE">
        <controlAdapters>
            <adapter controlType="System.Web.UI.WebControls.Label" 
                adapterType="Contoso.HideDisabledControlContosoAdapter" />
        </controlAdapters>
    </browser>
    <browser refID="IE">
        <controlAdapters>
            <adapter controlType="System.Web.UI.WebControls.Label" 
                adapterType="Contoso.HideDisabledControlContosoAdapter" />
        </controlAdapters>
    </browser>
</browsers>

Permissions

AspNetHostingPermission
for verifying at compilation time that the immediate caller has permission to call into the HideDisabledControlAdapter class. Associated enumeration: Minimal
AspNetHostingPermission
for verifying that any class derived from the HideDisabledControlAdapter class has at least the Minimal trust level. Associated enumeration:
Minimal

Inheritance Hierarchy

System..::.Object
  System.Web.UI.Adapters..::.ControlAdapter
    System.Web.UI.WebControls.Adapters..::.WebControlAdapter
      System.Web.UI.WebControls.Adapters..::.HideDisabledControlAdapter

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