WM_KEYUP
The WM_KEYUP
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.
WM_KEYUP
nVirtKey = (int) wParam; // virtual-key code
lKeyData = lParam; // key data
Parameters
nVirtKey
Value of wParam.
Specifies the virtual-key code of the nonsystem key.
lKeyData
Value of lParam.
Specifies the repeat count, scan code, extended-key flag, 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. The repeat count is always one
for a WM_KEYUP message. |
|
16-23 |
Specifies
the scan code. The value depends on the original equipment manufacturer
(OEM). |
|
24 |
Specifies
whether the key is an extended key, such as the right-hand ALT and CTRL keys that
appear on an enhanced 101- or 102-key keyboard. The value is 1 if it is an
extended key; otherwise, it is 0. |
|
25-28 |
Reserved;
do not use. |
|
29 |
Specifies
the context code. The value is always 0 for a WM_KEYUP message. |
|
30 |
Specifies
the previous key state. The value is always 1 for a WM_KEYUP message. |
|
31 |
Specifies
the transition state. The value is always 1 for a WM_KEYUP message. |
Return Values
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.
See Also