WM_CHAR
The WM_CHAR
message is posted to the window with the keyboard focus when a WM_KEYDOWN
message is translated by the TranslateMessageFHWOLF function. WM_CHAR contains the character
code of the key that was pressed.
WM_CHAR
chCharCode = (TCHAR) wParam; // character code
lKeyData = lParam; // key data
Parameters
chCharCode
Value of wParam.
Specifies the character code of the 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. |
|
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 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 Values
An
application should return zero if it processes this message.
Remarks
Because there
is not necessarily a one-to-one correspondence between keys pressed and
character messages generated, the information in the high-order word of the lKeyData
parameter is generally not useful to applications. The information in the
high-order word applies only to the most recent WM_KEYDOWN message that
precedes the posting of the WM_CHAR message.
For enhanced
101- and 102-key keyboards, extended keys are the right ALT and the right
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. Some other keyboards may
support the extended-key bit in the lKeyData parameter.
See Also