ImageButton.OnPreRender Method

Determines whether the image has been clicked prior to rendering on the client.

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

protected public:
virtual void OnPreRender (
	EventArgs^ e
) override
protected void OnPreRender (
	EventArgs e
)
protected internal override function OnPreRender (
	e : EventArgs
)
Not applicable.

Parameters

e

An EventArgs object that contains the event data.

The OnPreRender method is used primarily by control developers when deriving a custom class from the ImageButton control.

The following code example demonstrates how to override the OnPreRender method so that it always displays a thin border in a custom ImageButton server control.

NoteNote:

The following code sample uses the single-file code model and may not work correctly if copied directly into a code-behind file. The first part of the code sample must be copied into an empty text file that has an .aspx extension. The second part must be in a .cs file (for C#) or a .vb file (for Visual Basic). For more information on the Web Forms code model, see ASP.NET Web Page Code Model.

No code example is currently available or this language may not be supported.
<%@ 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 ImageButton - OnPreRender - VJ# Example</title>
    <script runat="server">
        void ImageButton1_Command(Object sender, CommandEventArgs e) 
        {
            // Redirect to the Microsoft home page.
            get_Response().Redirect("http://www.microsoft.com/");
        } //ImageButton1_Command
    </script>
    </head>
    <body>
        <form id="Form1" method="post" runat="server">
            <h3>Custom ImageButton - OnPreRender - VJ# Example</h3>
            
            <aspSample:CustomImageButtonOnPreRender 
              id="ImageButton1" 
              runat="server" 
              OnCommand="ImageButton1_Command" 
              AlternateText="Microsoft Home" 
              ImageUrl="http://www.microsoft.com/homepage/gif/bnr-microsoft.gif" />

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

	...

package Samples.AspNet.JSL.Controls; 

public class CustomImageButtonOnPreRender
    extends System.Web.UI.WebControls.ImageButton
{
    protected void OnPreRender(System.EventArgs e)
    {
        // Run the OnPreRender method on the base class.
        super.OnPreRender(e);
        // Always display the ImageButton with a thin border.
        this.set_BorderWidth(System.Web.UI.WebControls.Unit.Point(1));
    } //OnPreRender
} //CustomImageButtonOnPreRender

Windows 98, Windows Server 2000 SP4, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

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