Posted to the window with the keyboard focus when a WM_SYSKEYDOWN message is translated by the TranslateMessage function. It specifies the character code of a system character key — that is, a character key that is pressed while the ALT key is down.
The character code of the window menu key.
The repeat count, scan code, extended-key flag, context code, previous key-state flag, and transition-state flag, as shown in the following table.
The repeat count for the current message. The value is the number of times the keystroke was auto-repeated as a result of the user holding down the key. If the keystroke is held long enough, multiple messages are sent. However, the repeat count is not cumulative.
The scan code. The value depends on the original equipment manufacturer (OEM).
Indicates 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.
Reserved; do not use.
The context code. The value is 1 if the ALT key is held down while the key is pressed; otherwise, the value is 0.
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.
The transition state. The value is 1 if the key is being released, or it is 0 if the key is being pressed.
An application should return zero if it processes this message.
When the context code is zero, the message can be passed to the TranslateAccelerator function, which will handle it as though it were a standard key message instead of a system character-key message. This allows accelerator keys to be used with the active window even if the active window does not have the keyboard focus.
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; the PRINT SCRN key; the BREAK key; the NUMLOCK key; and the divide (/) and ENTER keys in the numeric keypad. Other keyboards may support the extended-key bit in the parameter.
Minimum supported client
|Windows 2000 Professional [desktop apps only]|
Minimum supported server
|Windows 2000 Server [desktop apps only]|