Close button

[Phil Myers]

Thanks a lot for the sample code - that was just what I needed to understand the idea. I appreciate it!

[jcfuller]

f you return non-zero to the WM_SYSCOMMAND|SC_CLOSE message, then the 'close' command is cancelled. This is useful for preventing a
dialog from closing, for instance if edit box data was found to be invalid or missing, etc.

If you are not using DDT you can return non-zero in the %WM_CLOSE message and get the same results.


James

[Lance Edmonds]

Clicking the 'X' (close) button on a window/dialog generates a %WM_SYSCOMMAND message (with CBWPARAM = %SC_CLOSE). The window/dialog handler (aka Windows) responds by sending a %WM_CLOSE message to your application.

If you return non-zero to the WM_SYSCOMMAND|SC_CLOSE message, then the 'close' command is cancelled. This is useful for preventing a dialog from closing, for instance if edit box data was found to be invalid or missing, etc.

It's not generally a 'good idea' to respond to CBCTL messages unless CBMSG = %WM_COMMAND (the value of CBMSG could coincide with a button id under circumstances other than %WM_COMMAND. With these point in mind, try this modified source code:

#DIM ALL
#COMPILE EXE
#OPTION VERSION4
#INCLUDE "WIN32API.INC"
 
%ID_Button1 = 101
%ID_Button2 = 102
 
CALLBACK FUNCTION MainCallback
   SELECT CASE CBMSG
          CASE %WM_INITDIALOG
               MSGBOX "Initializing ..."
          CASE %WM_SYSCOMMAND
               IF CBWPARAM = %SC_CLOSE THEN MSGBOX "App close"
'               FUNCTION = 1
          CASE %WM_CLOSE
               MSGBOX "Closing ..."
          CASE %WM_DESTROY
               MSGBOX "Destroying ..."
          CASE %WM_COMMAND
               SELECT CASE CBCTL
                      CASE %ID_Button1
                           IF CBCTLMSG = %BN_CLICKED THEN MSGBOX "Button1 clicked"
                      CASE %ID_Button2
                           IF CBCTLMSG = %BN_CLICKED THEN MSGBOX "Button2 clicked"
               END SELECT
   END SELECT
END FUNCTION  'MainCallback
 
FUNCTION PBMAIN () AS LONG
   LOCAL hDlg AS LONG
 
   DIALOG NEW 0,"TEST", , , 150, 80, %WS_SYSMENU TO hDlg
   CONTROL ADD BUTTON,hDlg,%ID_Button1,"Button1",10,20,50,20
   CONTROL ADD BUTTON,hDlg,%ID_Button2,"Button2",80,20,50,20
   DIALOG SHOW MODAL hDlg, CALL MainCallback
END FUNCTION

-------------
Lance
PowerBASIC Support
( mailto:[email protected][email protected]</A> )

Here's some test code to demo what I believe you're after, plus illustrate to newbies how to use a central callback function for all events (PBDLL6):

(to cut & paste the code below with proper indentation, click on the "Edit/Delete Message" button above this message, select all, copy and paste)

#DIM ALL
#COMPILE EXE
#OPTION VERSION4
#INCLUDE "WIN32API.INC"

%ID_Button1 = 101
%ID_Button2 = 102

GLOBAL ghDlg AS LONG

CALLBACK FUNCTION MainCallback

SELECT CASE CBMSG
CASE %WM_INITDIALOG
MSGBOX "Initializing ..."
CASE %WM_CLOSE
MSGBOX "Closing ..."
CASE %WM_DESTROY
MSGBOX "Destroying ..."
END SELECT

SELECT CASE CBCTL
CASE %ID_Button1
IF CBCTLMSG = %BN_CLICKED THEN MSGBOX "Button1 clicked"
CASE %ID_Button2
IF CBCTLMSG = %BN_CLICKED THEN MSGBOX "Button2 clicked"
END SELECT
END FUNCTION 'MainCallback

FUNCTION PBMAIN () AS LONG

DIALOG NEW 0,"TEST", , , 150, 80, %WS_SYSMENU TO ghDlg
CONTROL ADD BUTTON,ghDlg,%ID_Button1,"Button1",10,20,50,20
CONTROL ADD BUTTON,ghDlg,%ID_Button2,"Button2",80,20,50,20
DIALOG SHOW MODAL ghDlg, CALL MainCallback

END FUNCTION



[This message has been edited by William Fletcher (edited January 06, 2000).]

[jcfuller]

Phil,
See the WM_SYSCOMMAND in the help file.

James

[Phil Myers]

Can anyone tell me what message windows sends when the close button is clicked on a standard (%WS_SYSMENU) type dialog. In other words, the X in the upper right-hand corner? Thanks.