ImageButton.OnClick Method (System.Web.UI.WebControls)

OnClick Method

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This page is specific to

Microsoft Visual Studio 2008/.NET Framework 3.5

Other versions are also available for the following:

.NET Framework Class Library

ImageButton..::.OnClick Method

Raises the Click event and allows you to handle the Click event directly.

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

Syntax

Visual Basic (Declaration)

Protected Overridable Sub OnClick ( _
    e As ImageClickEventArgs _
)

Visual Basic (Usage)

Dim e As ImageClickEventArgs

Me.OnClick(e)

protected virtual void OnClick(
    ImageClickEventArgs e
)

Visual C++

protected:
virtual void OnClick(
    ImageClickEventArgs^ e
)

JScript

protected function OnClick(
    e : ImageClickEventArgs
)

Parameters

e: Type: System.Web.UI..::.ImageClickEventArgs
A System.Web.UI..::.ImageClickEventArgs that contains the event data.

Remarks

The Click event is raised when the ImageButton control is clicked. By using the OnClick event handler, you can programmatically determine the coordinates where the image is clicked. You can then code a response, based on the values of these coordinates. Note that the origin (0, 0) is located at the upper left corner of the image.

Raising an event invokes the event handler through a delegate. For more information, see How to: Consume Events in a Web Forms Application.

The OnClick method also allows derived classes to handle the event without attaching a delegate. This is the preferred technique for handling the event in a derived class.

Notes to Inheritors:

When overriding OnClick in a derived class, be sure to call the base class's OnClick method so that registered delegates receive the event.

Examples

The following example demonstrates how to specify and code a handler for the Click event to display the coordinates where the user clicks the image.

Note:
The following code sample uses the single-file code model and may not work correctly if copied directly into a code-behind file. This code sample must be copied into an empty text file that has an .aspx extension. For more information on the Web Forms code model, see ASP.NET Web Page Code Model.

Visual Basic

<%@ Page Language="VB" AutoEventWireup="True" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html  >
<head>
    <title>ImageButton Sample</title>
<script language="VB" runat="server">

      Sub ImageButton_Click(sender As Object, e As ImageClickEventArgs) 
         Label1.Text = "You clicked the ImageButton control at the coordinates: (" & _ 
                       e.X.ToString() & ", " & e.Y.ToString() & ")"
      End Sub

   </script>

</head>

<body>

   <form id="form1" runat="server">

      <h3>ImageButton Sample</h3>

      Click anywhere on the image.<br /><br />

      <asp:ImageButton id="imagebutton1" runat="server"
           AlternateText="ImageButton 1"
           ImageAlign="left"
           ImageUrl="images/pict.jpg"
           OnClick="ImageButton_Click"/>

      <br /><br />

      <asp:label id="Label1" runat="server"/>

   </form>

</body>
</html>

<%@ 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  >
<head>
    <title>ImageButton Sample</title>
<script language="C#" runat="server">

      void ImageButton_Click(object sender, ImageClickEventArgs e) 
      {
         Label1.Text = "You clicked the ImageButton control at the coordinates: (" + 
                       e.X.ToString() + ", " + e.Y.ToString() + ")";
      }

   </script>

</head>

<body>

   <form id="form1" runat="server">

      <h3>ImageButton Sample</h3>

      Click anywhere on the image.<br /><br />

      <asp:ImageButton id="imagebutton1" runat="server"
           AlternateText="ImageButton 1"
           ImageAlign="left"
           ImageUrl="images/pict.jpg"
           OnClick="ImageButton_Click"/>

      <br /><br />

      <asp:label id="Label1" runat="server"/>

   </form>

</body>
</html>

JScript

<%@ Page Language="JScript" AutoEventWireup="True" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html  >
<head>
    <title>ImageButton Sample</title>
<script language="JSCRIPT" runat="server">

      function ImageButton_Click(sender : Object, e : ImageClickEventArgs) {
         Label1.Text = "You clicked the ImageButton control at the coordinates: (" + e.X.ToString() + ", " + e.Y.ToString() + ")"
      }

   </script>

</head>

<body>

   <form id="form1" runat="server">

      <h3>ImageButton Sample</h3>

      Click anywhere on the image.<br /><br />

      <asp:ImageButton id="imagebutton1" runat="server"
           AlternateText="ImageButton 1"
           ImageAlign="left"
           ImageUrl="images/pict.jpg"
           OnClick="ImageButton_Click"/>

      <br /><br />

      <asp:label id="Label1" runat="server"/>

   </form>

</body>
</html>

Platforms

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.

Version Information

.NET Framework

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

Reference

ImageButton Class

ImageButton Members

System.Web.UI.WebControls Namespace

Click

System.Web.UI..::.ImageClickEventArgs

Other Resources

ImageButton Web Server Control Declarative Syntax

Button Web Server Controls Overview

How to: Consume Events in a Web Forms Application