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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
)

Parameters

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"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
    <head>
        <title>Custom TextBox - OnPreRender - C# Example</title>
    </head>
    <body>
        <form id="Form1" method="post" runat="server">
            <h3>Custom TextBox - OnPreRender - C# Example</h3>

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

        </form>
    </body>
</html>
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. 
      base.OnPreRender(e);

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

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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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