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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)

'Declaration
Protected Overridable Sub OnClick ( _
	e As EventArgs _
)

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="VB" %>

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

<script runat="server">

    Sub GreetingBtn_Click(ByVal sender As Object, _
                          ByVal e As EventArgs)

        ' When the button is clicked,
        ' change the button text, and disable it.

        Dim clickedButton As Button = sender
        clickedButton.Text = "...button clicked..."
        clickedButton.Enabled = False

        ' Display the greeting label text.
        GreetingLabel.Visible = True
    End Sub

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>Button Example</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>

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1
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