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Shape.OnKeyDown Method

Raises the KeyDown event.

Namespace:  Microsoft.VisualBasic.PowerPacks
Assembly:  Microsoft.VisualBasic.PowerPacks.Vs (in Microsoft.VisualBasic.PowerPacks.Vs.dll)

protected internal virtual void OnKeyDown(
	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 Raising an Event.

The OnKeyDown method also enables 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 you override OnKeyDown in a derived class, be sure to call the OnKeyDown method of the base class so that registered delegates receive the event.

The following example is a method that is executed when the Click event occurs. The Shape class has several methods with the name pattern OnEventName that execute methods when the EventName event occurs. (EventName represents the name of the corresponding event.)

The following example demonstrates how to override the OnClick and OnLostFocus methods in a class that derives from LineShape.

public class HighlightLine :
    LineShape
{
    protected override void OnClick(EventArgs e)
    {
        // Change the color of the line when clicked. 
        this.BorderColor = Color.Red;
        base.OnClick(e);
    }
    protected override void OnLostFocus(System.EventArgs e)
    {
        // Change the color of the line when focus is changed. 
        this.BorderColor = Color.Black;
        base.OnLostFocus(e);
    }
}

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