The WM_CHAR message is posted to the window with the keyboard focus when a WM_KEYDOWN message is translated by the TranslateMessage function. WM_CHAR contains the character code of the key that was pressed.
WM_CHAR chCharCode = (TCHAR) wParam; // character code lKeyData = lParam; // key data
|
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. If the keystroke is held long enough, multiple messages are sent. However, the repeat count is not cumulative. |
|
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. |
An application should return zero if it processes this message.
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.