Code:
' SIMPLE 'WRITE YOUR OWN' ENUM FUNCTION FOR PB/Win 7.0
' Author: Michael Mattias Racine WI
' September 2002
' Compiler: PB/Win v 7.0
' ========================================================================
' This demo shows how to write a simple enumeration function to process
' each element of a string array one at a time with an option to quit
' partway through.
' ========================================================================
' The parameters for the callback function 'EnumElementsCallBackFunction'
' were designed specifically to allow the callback function to do 'what it
' has to do' and no more.
#COMPILE EXE
#INCLUDE "Win32API.INC"
%USER_ABORT = 999
%ID_LABEL = 101
%ID_BUTTON = 102
%N_ELEMENTS = 6 ' number of elements in array
' Optional DECLARE for CALL DWORD: not needed in this demo because
' the function appears in the source code PRIOR to its use
' DECLARE FUNCTION EnumElementsCallBackFunction(BYVAL hDlg AS LONG, BYVAL hCtrl AS LONG, s AS STRING) AS LONG
' The function which is called for each array element when the enumeration occurs.
' Parameters needed: hDlg, control ID and text so we can CONTROL SET TEXT
FUNCTION EnumElementsCallBackFunction(BYVAL hDlg AS LONG, BYVAL hCtrl AS LONG, s AS STRING) AS LONG
LOCAL J AS LONG
' set the text of the label control fo this element
CONTROL SET TEXT hDlg, hCtrl, S
' does user want to continue?
J = MSGBOX ("Continue Enumeration?", %MB_YESNO OR %MB_TASKMODAL OR %MB_ICONQUESTION, "Yo! Response Required!")
IF J = %IDYES THEN
FUNCTION = %TRUE ' yes, continue the enumeration
ELSE
FUNCTION = %FALSE ' no, terminate now
END IF
END FUNCTION
FUNCTION EnumArrayElements (BYVAL hDlg AS LONG, BYVAL hCtrl AS LONG, S() AS STRING, BYVAL dwCallbackAddress AS DWORD) AS LONG
LOCAL I AS LONG, lContinue AS LONG
' for each element of the passed array, call the callback function
' with the defined parameters exactly once.
FOR I = LBOUND(S,1) TO UBOUND (s,1)
CALL DWORD dwCallBackAddress USING EnumElementsCallBackFunction (hDlg, hCtrl, S(I)) TO lContinue
IF ISFALSE lContinue THEN
FUNCTION = %USER_ABORT : EXIT FUNCTION
END IF
NEXT
' If we get this far, the user allowed the enumeration to continue
' until there was nothing left to do.
FUNCTION = 0
END FUNCTION
CALLBACK FUNCTION DialogProc
LOCAL X() AS STRING, I AS LONG, umsg AS STRING
IF CBMSG = %WM_COMMAND THEN
IF CBCTL = %ID_BUTTON THEN
REDIM X(%N_ELEMENTS)
FOR I = 0 TO %N_ELEMENTS
X(I) = "Array Element # " & STR$(I)
NEXT
I = EnumArrayElements(CBHNDL, %ID_LABEL, X(), CODEPTR(EnumElementsCallbackFunction))
IF I = %USER_ABORT THEN
uMsg ="User terminated enumeration before completion"
ELSE
uMsg = "User Allowed enumeration to complete"
END IF
MSGBOX uMsg, %MB_OK OR %MB_ICONINFORMATION, "Enumeration Results"
ELSEIF CBCTL = %IDCANCEL THEN
DIALOG END CBHNDL, 0
END IF
END IF
END FUNCTION
FUNCTION PBMAIN() AS LONG
LOCAL hDlg AS LONG
DIALOG NEW 0&, "Enum & Callback Demo", 10, 10, 120,100 TO hDlg
CONTROL ADD LABEL ,hDlg, %ID_LABEL, "<null>", 10, 10, 60, 12
CONTROL ADD BUTTON ,hDlg, %ID_BUTTON, "Do it", 10, 30, 40,14
CONTROL ADD BUTTON, hDlg, %IDCANCEL, "Quit", 10, 50, 40,14
DIALOG SHOW MODAL hDlg, CALL DialogProc
END FUNCTION
' ** END OF FILE **
------------------
Michael Mattias
Tal Systems Inc.
Racine WI USA
[email protected]
www.talsystems.com