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Control.OnKeyUp Method

Raises the KeyUp event.

Namespace:  System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

protected virtual void OnKeyUp(
	KeyEventArgs e
)

Parameters

e
Type: System.Windows.Forms.KeyEventArgs

A KeyEventArgs that contains the event data.

Raising an event invokes the event handler through a delegate. For more information, see Handling and Raising Events.

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

The following code example uses the KeyUp event with the Help class to display pop-up style help to the user.

// This example demonstrates how to use the KeyUp event with the Help class to display 
// pop-up style help to the user of the application. When the user presses F1, the Help 
// class displays a pop-up window, similar to a ToolTip, near the control. This example assumes 
// that a TextBox control, named textBox1, has been added to the form and its KeyUp 
// event has been contected to this event handler method. 
private void textBox1_KeyUp(object sender, System.Windows.Forms.KeyEventArgs e)
{
    // Determine whether the key entered is the F1 key. Display help if it is. 
    if(e.KeyCode == Keys.F1)
    {
        // Display a pop-up help topic to assist the user.
        Help.ShowPopup(textBox1, "Enter your first name", new Point(textBox1.Right, this.textBox1.Bottom));
    }
}

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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