HtmlInputImage.OnPreRender Method
.NET Framework 3.0
Raises the PreRender event.
Namespace: System.Web.UI.HtmlControls
Assembly: System.Web (in system.web.dll)
Assembly: System.Web (in system.web.dll)
The OnPreRender method is called just prior to rendering the HtmlInputImage control. The OnPreRender method is used primarily by control developers extending the functionality of the HtmlInputImage control.
Notes to Inheritors: When overriding the OnPreRender method in a derived class, be sure to call the base class's OnPreRender method so that registered delegates receive the PreRender event.The following code example demonstrates how to override the OnPreRender method so that it always displays a custom HtmlInputImage server control with no border.
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.JSL.Controls" Assembly="Samples.AspNet.JSL" %>
<%@ Page Language="VJ#" 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 HtmlInputImage - Method - VJ# Example</title>
<script runat="server">
void Page_Load(Object sender, EventArgs e)
{
HtmlInputImage1.get_Attributes().Add("onclick",
"alert('Hello client-side world.');");
} //Page_Load
void HtmlInputImage1_ServerClick(Object sender, ImageClickEventArgs e)
{
Div1.set_InnerHtml("Hello server-side world.");
} //HtmlInputImage1_ServerClick
</script>
</head>
<body>
<form id="Form1" method="post" runat="server">
<h3>Custom HtmlInputImage - Method - VJ# Example</h3>
<aspSample:CustomHtmlInputImageOnPreRender
id="HtmlInputImage1"
name="HtmlInputImage1"
runat="server"
type="image"
src="http://www.microsoft.com/homepage/gif/bnr-microsoft.gif"
onserverclick="HtmlInputImage1_ServerClick" /><br />
<br />
<div
id="Div1"
runat="server"
style="DISPLAY: inline; WIDTH: 256px; HEIGHT: 15px" />
</form>
</body>
</html>
package Samples.AspNet.JSL.Controls;
public class CustomHtmlInputImageOnPreRender
extends System.Web.UI.HtmlControls.HtmlInputImage
{
protected void OnPreRender(System.EventArgs e)
{
// Call the base's OnPreRender method.
super.OnPreRender(e);
// Always display the HtmlInputImage with no border.
this.set_Border(0);
} //OnPreRender
} //CustomHtmlInputImageOnPreRender
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