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Button.OnClick Method

Raises the Click event of the Button control.

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

protected virtual void OnClick(
	EventArgs e
)

Parameters

e
Type: System.EventArgs

The event data.

The Click event is raised when the Button control is clicked. This event is commonly used when no command name is associated with the Button control (for instance, with a Submit button).

Raising an event invokes the event handler through a delegate. For more information, see Raising an Event.

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.

The following code example demonstrates how to specify and code an event handler for the Click event in order to display a simple message on the Web page.

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

    void Page_Load(Object sender, EventArgs e)
    {
        // Manually register the event-handling method for 
        // the Click event of the Button control.
        Button1.Click += new EventHandler(this.GreetingBtn_Click);
    }

    void GreetingBtn_Click(Object sender,
                           EventArgs e)
    {
        // When the button is clicked, 
        // change the button text, and disable it.

        Button clickedButton = (Button)sender;
        clickedButton.Text = "...button clicked...";
        clickedButton.Enabled = false;

        // Display the greeting label text.
        GreetingLabel.Visible = true;
    }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>Untitled Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
      <h3>Simple Button Example</h3>

      <asp:Button id="Button1"
           Text="Click here for greeting..."
           OnClick="GreetingBtn_Click" 
           runat="server"/>
      <br />
      <br />
      <asp:Label ID="GreetingLabel" runat="server" 
                 Visible="false" Text="Hello World!" />
    </div>
    </form>
</body>
</html>

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.

.NET Framework

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

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