WM_KEYUP (Compact 2013)

3/28/2014

This message is posted to the window with the keyboard focus when a nonsystem key is released. A nonsystem key is a key that is pressed when the ALT key is not pressed, or a keyboard key that is pressed when a window has the keyboard focus.

Syntax

WM_KEYUP nVirtKey = (int) wParam; 
    lKeyData = lParam;

Parameters

• nVirtKey
  Specifies the virtual-key code of the nonsystem key.

• lKeyData
  Specifies the repeat count, context code, previous key-state flag, and transition-state flag, as shown in the following table.

  Value	Description
  0-15	Specifies the repeat count. The value is the number of times the keystroke is repeated as a result of the user holding down the key.
  16-23	Specifies the scan code. This value depends on the original equipment manufacturer.
  29	Specifies the context code. The value is 1 if the ALT key is held down while the key is pressed; otherwise, the value is 0.
  30	Specifies the previous key state. The value is 1 if the key is down before the message is sent, or it is 0 if the key is up.
  31	Specifies the transition state. The value is 1 if the key is being released, or it is 0 if the key is being pressed.

Return Value

An application should return zero if it processes this message.

• Default Action
  The DefWindowProc function sends a WM_SYSCOMMAND message to the top-level window if the F10 key or the ALT key was released. The wParam parameter of the message is set to SC_KEYMENU.

Remarks

For enhanced 101- and 102-key keyboards, extended keys are the right ALT and CTRL keys on the main section of the keyboard; the INS, DEL, HOME, END, PAGE UP, PAGE DOWN and arrow keys in the clusters to the left of the numeric keypad; and the divide (/) and ENTER keys in the numeric keypad. Other keyboards may support the extended-key bit in the lKeyData parameter.

Requirements

See Also

Reference

Keyboard Messages
DefWindowProc
WM_KEYDOWN
WM_SYSCOMMAND