TWinControl.OnKeyDown property

Declaration

property OnKeyDown: TKeyEvent read FOnKeyDown write FOnKeyDown;

Description

OnKeyDown is a TKeyEvent property with the event handler signalled to handle a key down event for the control. The event handler receives keys including control and other non-visual keys. It is signalled (when assigned) from the KeyDown method.

The Sender argument contains the control for the key event. It must be cast to TControl or TwinControl type to access properties or methods specific to the descendent classes.

The Key argument contains the virtual keyboard constant for the key event (like VK_F1 or VK_NUMPAD5). It is a variable argument and can be modified in the event handler. Set Key to VK_UNKNOWN if the handler routine has performed the actions needed to handle the key event. Otherwise, Key is passed to other OnKeyDown handlers at the form or application level.

Shift is a set type which contains the modifiers for the key down event like: Ctrl, Shift, Alt, or Meta.

Use OnKeyUp to perform actions needed when the key is released.

Use OnKeyPress or OnUTF8KeyPress to implement a handler routine for printable character values.

• https://docs.kde.org/stable5/en/khelpcenter/fundamentals/kbd.html
• https://help.gnome.org/users/gnome-help/stable/shell-keyboard-shortcuts.html.en
• https://developer.gnome.org/hig/reference/keyboard.html
• https://support.microsoft.com/en-us/windows/keyboard-shortcuts-in-windows-dcc61a57-8ff0-cffe-9796-cb9706c75eec
• https://support.apple.com/en-us/102650
• https://en.wikipedia.org/wiki/Table_of_keyboard_shortcuts#Comparison_of_keyboard_shortcuts

See also

• KeyDown
• OnKeyUp
• OnKeyPress
• TKeyEvent