PlaceHolder 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

PlaceHolder Class

Stores dynamically added server controls on the Web page.

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

Syntax

Visual Basic (Declaration)

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

Visual Basic (Usage)

Dim instance As PlaceHolder

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

Visual C++

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

JScript

public class PlaceHolder extends Control

ASP.NET

<asp:PlaceHolder />

Remarks

Use the PlaceHolder control as a container to store server controls that are dynamically added to the Web page. The PlaceHolder control does not produce any visible output and is used only as a container for other controls on the Web page. You can use the Control..::.Controls collection to add, insert, or remove a control in the PlaceHolder control.

Topic	Location
How to: Add Controls to an ASP.NET Web Page Programmatically	Building ASP .NET Web Applications
How to: Add Controls to an ASP.NET Web Page Programmatically	Building ASP .NET Web Applications
How to: Add Controls to an ASP.NET Web Page Programmatically	Building ASP .NET Web Applications in Visual Studio
How to: Add Controls to an ASP.NET Web Page Programmatically	Building ASP .NET Web Applications in Visual Studio
How to: Add PlaceHolder Web Server Controls to a Web Forms Page	Building ASP .NET Web Applications in Visual Studio
How to: Add PlaceHolder Web Server Controls to a Web Forms Page	Building ASP .NET Web Applications in Visual Studio
How to: Add PlaceHolder Web Server Controls to a Web Forms Page	Building ASP .NET Web Applications
How to: Add PlaceHolder Web Server Controls to a Web Forms Page	Building ASP .NET Web Applications
How to: Add PlaceHolder Web Server Controls to a Web Forms Page (Visual Studio)	Building ASP .NET Web Applications in Visual Studio
How to: Create Instances of ASP.NET User Controls Programmatically	Building ASP .NET Web Applications
How to: Create Instances of ASP.NET User Controls Programmatically	Building ASP .NET Web Applications
How to: Create Instances of ASP.NET User Controls Programmatically	Building ASP .NET Web Applications in Visual Studio
How to: Create Instances of ASP.NET User Controls Programmatically	Building ASP .NET Web Applications in Visual Studio
How to: Create Templated ASP.NET User Controls	Building ASP .NET Web Applications
How to: Create Templated ASP.NET User Controls	Building ASP .NET Web Applications
How to: Create Templated ASP.NET User Controls	Building ASP .NET Web Applications in Visual Studio
How to: Create Templated ASP.NET User Controls	Building ASP .NET Web Applications in Visual Studio

Examples

The following code example demonstrates how to dynamically add controls to the PlaceHolder control.

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>
    <title>PlaceHolder Example</title>
<script runat="server">

      Sub Page_Load(Sender As Object, e As EventArgs)

         Dim myButton As HtmlButton = New HtmlButton()

         myButton.InnerText = "Button 1"
         PlaceHolder1.Controls.Add(myButton)

         myButton = New HtmlButton()
         myButton.InnerText = "Button 2"
         PlaceHolder1.Controls.Add(myButton)

         myButton = New HtmlButton()
         myButton.InnerText = "Button 3"
         PlaceHolder1.Controls.Add(myButton)

         myButton = New HtmlButton()
         myButton.InnerText = "Button 4"
         PlaceHolder1.Controls.Add(myButton)

      End Sub

   </script>

</head>

<body>
   <form id="form1" runat="server">
      <h3>PlaceHolder Example</h3>

      <asp:PlaceHolder id="PlaceHolder1" 
           runat="server"/>
   </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>
    <title>PlaceHolder Example</title>
<script runat="server">

      void Page_Load(Object sender, EventArgs e)
      {
         HtmlButton myButton = new HtmlButton();

         myButton.InnerText = "Button 1";
         PlaceHolder1.Controls.Add(myButton);

         myButton = new HtmlButton();
         myButton.InnerText = "Button 2";
         PlaceHolder1.Controls.Add(myButton);

         myButton = new HtmlButton();
         myButton.InnerText = "Button 3";
         PlaceHolder1.Controls.Add(myButton);

         myButton = new HtmlButton();
         myButton.InnerText = "Button 4";
         PlaceHolder1.Controls.Add(myButton);
      }

   </script>

</head>

<body>
   <form id="form1" runat="server">
      <h3>PlaceHolder Example</h3>

      <asp:PlaceHolder id="PlaceHolder1" 
           runat="server"/>
   </form>
</body>
</html>

.NET Framework Security

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..::.PlaceHolder

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 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, 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

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

Reference

PlaceHolder Members

System.Web.UI.WebControls Namespace

System.Web.UI..::.Control

Control..::.Controls

Other Resources

PlaceHolder Web Server Control Overview