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TextBox.OnPreRender Method

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

Registers client script for generating postback events prior to rendering on the client, if AutoPostBack is true.

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

protected internal override void OnPreRender(
	EventArgs e


Type: System.EventArgs

An EventArgs that contains the event data.

The following code example demonstrates how to override the OnPreRender method so that it always displays a one-point border in a custom TextBox server control.

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" 
<html xmlns="" >
        <title>Custom TextBox - OnPreRender - C# Example</title>
        <form id="Form1" method="post" runat="server">
            <h3>Custom TextBox - OnPreRender - C# Example</h3>

              runat="server">Hello World!

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

namespace Samples.AspNet.CS.Controls
  [AspNetHostingPermission(SecurityAction.Demand, Level=AspNetHostingPermissionLevel.Minimal)]
  public sealed class CustomTextBoxOnPreRender : System.Web.UI.WebControls.TextBox
    protected override void OnPreRender(System.EventArgs e)
      // Run the OnPreRender method on the base class. 

      // Display the TextBox with a 1 point border. 
      this.BorderWidth = System.Web.UI.WebControls.Unit.Point(1);

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.

.NET Framework

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