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
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Value |
Description |
|
0-15 |
Specifies the repeat count for the current message. The value is the number of times the keystroke is auto-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. |
An application should return zero if it processes this message.
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.
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.
DefWindowProc, WM_KEYDOWN, WM_SYSCOMMAND
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