UIElement.KeyDown Event

May 11, 2014

Occurs when a keyboard key is pressed while the UIElement has focus.

Namespace:  System.Windows
Assembly:  System.Windows (in System.Windows.dll)
XMLNS for XAML: Not mapped to an xmlns.

'Declaration
Public Event KeyDown As KeyEventHandler
<uiElement KeyDown="eventhandler"/>

Use a handler based on KeyEventHandler to handle this event. To determine the specific key that was pressed, check Key or PlatformKeyCode. To determine if any modifier keys are pressed, check Keyboard.Modifiers.

The KeyDown event is a bubbling event. This means that if multiple KeyDown event handlers are registered for a sequence of objects connected by parent-child relationships in the object tree, the event is received by each object in that relationship. The bubbling metaphor indicates that the event starts at the object that has focus while the key is pressed, and works its way up the object tree. For a bubbling event, the sender available to the event handler identifies the object where the event is handled, not necessarily the object that actually received the input condition that initiated the event. To get the object that initiated the event, use the OriginalSource value of the event's RoutedEventArgs event data.

Element focus and the ability to initiate a keyboard event are related concepts. In order to generate the KeyDown event, the UIElement must have focus.

On the TextBox class, there is a TextChanged event that has potential interactions with KeyDown. For details, see TextBox.

KeyUp and OnKeyUp

Controls that inherit KeyDown can provide handling for the event that acts as handler for all instances, by overriding the OnKeyDown method. This might include marking the Handled value of the event as true, which has the effect of suppressing further handling of the KeyDown event for some or all keys on any instance of the control (and potentially any subclass of the control). For more information, see OnKeyDown.

You can also register handlers such that they are invoked even for already-handled routed events. For more information, see AddHandler.

Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Windows Phone

Show:
© 2014 Microsoft