How to send a key like does SendKey in VB ?

Posted on 1998-07-15
Last Modified: 2012-06-27
I'm in a derived CFileDialog class with the OFN_EXPLORER style and I would like, in a response of a button, send the 'F2' key to the API in order to rename the selected file.
!!! : I don't want to use the SendInput Method.

Please can someone help me.

Thanks a lot !! ;-)
Question by:acabadet
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Expert Comment

ID: 1167810
Fire a WM_CHAR at the dialog using either ::SendMessage() or CWnd::SendMessage(). Details of WM_CHAR:

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.

chCharCode = (TCHAR) wParam;    // character code
lKeyData = lParam;              // key data

Value of wParam. Specifies the character code of the key.


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
 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.
 Specifies the scan code. The value depends on the original equipment manufacturer (OEM).
 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.
 Reserved; do not use.
 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.
 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.
 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.

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.


Author Comment

ID: 1167811
The SendMessage function doesn't work. I 've already tried !!!
LVL 22

Accepted Solution

nietod earned 50 total points
ID: 1167812
answer coming.
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LVL 22

Expert Comment

ID: 1167813
Sorry for the wait there.  I can never remeber the name of the function.  You want Keybd_event().  This is the most reliable way to "fake" a key event.  It takes care of sending the right pairs of messages with the right flags set etc.

Expert Comment

ID: 1167814
Grumble.  Be good to mention it, then.

Try SendMessage() with WM_USER +302 (decimal), which is 0x52e, sending to the Dialog.

LVL 22

Expert Comment

ID: 1167815
Is this answer sufficient?  If so, you should grade the answer.  If not, let us know what the problem is.

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