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HtmlButton.OnPreRender Method

Raises the PreRender event and registers client script for generating a postback.

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

protected internal override void OnPreRender(
	EventArgs e
)

Parameters

e
Type: System.EventArgs

An EventArgs that contains event data.

The OnPreRender method is used primarily by control developers extending the functionality of the HtmlButton control.

The following code example demonstrates how to override the OnPreRender method in a custom server control so that it always displays the HtmlButton with bold text.

<%@ 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 HtmlButton - OnPreRender - C# Example</title>
    <script runat="server">
      void Page_Load(Object sender, EventArgs e)
      {
        HtmlButton1.Attributes.Add("onclick","alert('Hello client-side world.');");
      }

      void HtmlButton1_ServerClick(Object sender, EventArgs e)
      {
        Div1.InnerHtml = "Hello server-side world.";
      }
    </script>
  </head>
  <body>
    <form id="Form1" method="post" runat="server">
      <h3>Custom HtmlButton - OnPreRender - C# Example</h3>

      <aspSample:CustomHtmlButtonOnPreRender
        id="HtmlButton1"
        runat="server"
        type="button"
        onserverclick="HtmlButton1_ServerClick"
        name="HtmlButton1">Html Button</aspSample:CustomHtmlButtonOnPreRender>&nbsp;&nbsp;

      <div id="Div1" runat="server"
        style="DISPLAY: inline; WIDTH: 256px; HEIGHT: 15px" />
    </form>
  </body>
</html>
using System.Web;
using System.Security.Permissions;

namespace Samples.AspNet.CS.Controls
{
    [AspNetHostingPermission(SecurityAction.Demand, Level = AspNetHostingPermissionLevel.Minimal)]
    public sealed class CustomHtmlButtonOnPreRender : System.Web.UI.HtmlControls.HtmlButton
    {
        protected override void OnPreRender(System.EventArgs e)
        {
            // Call the base class's OnPreRender method. 
            base.OnPreRender(e);

            // Always display the HtmlButton with bold text. 
            this.Style.Add("font-weight", "bold");
        }
    }
}

.NET Framework

Supported in: 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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