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TextBox.AddParsedSubObject Method

This API supports the .NET Framework infrastructure and is not intended to be used directly from your code.

Overridden to allow only literal controls to be added as the Text property.

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

protected override void AddParsedSubObject(
	Object obj
)

Parameters

obj
Type: System.Object
An Object that represents the parsed element.

ExceptionCondition
HttpException

obj is not of type LiteralControl.

The following code example demonstrates how to override the AddParsedSubObject method in a custom server control so that it always sets the Text property to the parsed object's Text property if the parsed object is a Literal control, and throws an exception otherwise.

Security noteSecurity Note

This example has a text box that accepts user input, which is a potential security threat. By default, ASP.NET Web pages validate that user input does not include script or HTML elements. For more information, see Script Exploits Overview.


<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS.Controls" Assembly="Samples.AspNet.CS" %>
<%@ 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>
        <title>Custom TextBox - AddParsedSubObject - C# Example</title>
    </head>
    <body>
        <form id="Form1" method="post" runat="server">
            <h3>Custom TextBox - AddParsedSubObject - C# Example</h3>

            <aspSample:CustomTextBoxAddParsedSubObject 
              id="TextBox1" 
              runat="server">Hello World!
            </aspSample:CustomTextBoxAddParsedSubObject>

        </form>
    </body>
</html>



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

namespace Samples.AspNet.CS.Controls
{
  [AspNetHostingPermission(SecurityAction.Demand, Level=AspNetHostingPermissionLevel.Minimal)]
  public sealed class CustomTextBoxAddParsedSubObject : System.Web.UI.WebControls.TextBox
  {
    protected override void AddParsedSubObject(object obj)
    {
      // If the object is a LiteralControl, then set this control's Text property.
      if (obj is System.Web.UI.LiteralControl) 
      {
        this.Text = ((System.Web.UI.LiteralControl)obj).Text;
      }
      else 
      {
        throw new System.Web.HttpException("You cannot have a child control of type " + obj.GetType().Name.ToString());
      }
    }
  }
}


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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

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