Announcement

**Lance Edmonds** · 28 May 2000, 03:27 AM

Todd, I can't run your code because the TABDDT.INC file is missing. However, some general comments shpould help you here anyway:

1. The parent of the tab control (the dialog) should have the style %WS_EX_CONTROLPARENT, and the individual tab pages (modeless dialogs) should have the style %DS_CONTROL. These "page dialogs" should be started with DIALOG SHOW MODELESS, and your app should provide a message pump that runs for the duration of the modeless dialogs.

2. Drawing on dialogs (or controls) should only occur during %WM_PAINT. Therefore, your code should only be calculating drawing positions duing %WM_MOUSEMOVE, but then call InvalidateRect() followed by UpdateWindow() which causes a %WM_PAINT even to occur. Then, using the these calculated positions, your %WM_PAINT handler does the drawing. This ensures that your "lines" are repainted correctly if the dialog needs to be repainted because of any reason other than the forced repaint your code is issuing.

3. The tab callback issues are probably caused by whatever is in TABDDT.INC. I suspect part of the problem relates to #1 and #4.

4. The child modeless dialogs that form the tab pages should be children of the DIALOG that contains the tab control, NOT the tab control itself! This is opposite to how VB does things, but it is the correct way to do it with DDT and/or SDK-style applications.

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

**Semen Matusovski** · 28 May 2000, 09:41 AM

Todd --
probably, you will understand, how to organize callback functions from my training code (based on sample from http://www.powerbasic.com/files/pub/pbwin/ )

Code:

   #Compile Exe
   #Register None
   #Dim All
   #Include "commctrl.inc"

   %ID_TAB = 1001
   
   CallBack Function TabProc1
      Select Case CbMsg
         Case %WM_INITDIALOG
            Control Add TextBox, CbHndl, -1, "Tab 1", 0, 0, 255, 140, , %WS_EX_CLIENTEDGE
      End Select
   End Function
   CallBack Function TabProc2
      Select Case CbMsg
         Case %WM_INITDIALOG
            Control Add TextBox, CbHndl, -1, "Tab 2", 0, 0, 255, 140, , %WS_EX_CLIENTEDGE
      End Select
   End Function
   CallBack Function TabProc3
      Select Case CbMsg
         Case %WM_INITDIALOG
            Control Add Button, CbHndl, -1, "Tab 3", 0, 0, 255, 140
      End Select
   End Function

   CallBack Function MainDlgProc
      Static LastIdx As Long, hWndTab() As Long
      Local tie As TC_ITEM, i As Long, Caption As String
      %nTabCh = 3
      Select Case CbMsg
         Case %WM_INITDIALOG
            ReDim hWndTab(1 To %nTabCh)
            For i = 1 To %nTabCh
               Dialog New CbHndl, "", 20, 35, 255, 140, %DS_CONTROL Or %WS_CHILD To hWndTab(i)
               Select Case i
                  Case 1
                     Dialog Show Modeless hWndTab(i) Call TabProc1: Caption = " One "
                  Case 2
                     Dialog Show Modeless hWndTab(i) Call TabProc2: Caption = " Two "
                  Case 3
                     Dialog Show Modeless hWndTab(i) Call TabProc3: Caption = " Three "
               End Select
               If i = 1 Then ShowWindow hWndTab(i), %SW_SHOW Else _
                  ShowWindow hWndTab(i), %SW_HIDE
               tie.mask = %TCIF_TEXT Or %TCIF_IMAGE
               tie.iImage = -1
               tie.pszText = StrPtr(Caption)
               TabCtrl_InsertItem GetDlgItem(CbHndl, %ID_TAB), i, tie
            Next
            SetFocus GetDlgItem(CbHndl, %ID_TAB)
         Case %WM_NOTIFY
            Local lpNmh As NMHDR Ptr
            lpNmh = CbLparam
            Select Case @lpNmh.Code
               Case %TCN_LAST To %TCN_FIRST
                  Select Case @lpNmh.idFrom
                     Case %ID_TAB
                       Select Case @lpNmh.Code
                          Case %TCN_SELCHANGE
                             i = TabCtrl_GetCurSel(GetDlgItem(CbHndl,%ID_TAB))
                             ShowWindow hWndTab(LastIdx + 1), %SW_HIDE
                             LastIdx = i: ShowWindow hWndTab(LastIdx + 1), %SW_SHOW
                       End Select
               End Select
            End Select
      End Select
   End Function

   Function PbMain
      Local hDlg As Long
      InitCommonControls
      Dialog New 0, "DDT - Tab Example",,, 300, 200, _
         %WS_MINIMIZEBOX Or %WS_CAPTION Or %WS_SYSMENU, %WS_EX_CONTROLPARENT To hDlg
      Control Add "SysTabControl32", hDlg, %ID_TAB, "", 10, 10, 280, 180, %WS_CHILD Or %WS_VISIBLE
      Dialog Show Modal hDlg Call MainDlgProc
   End Function

**Todd Wasson** · 28 May 2000, 03:03 PM

Lance, thank you for the tips on handling drawing via %WM_PAINT, InvalidateRect() and UpdateWindow(). This version works as planned.

Code:

#COMPILE EXE
#INCLUDE "commctrl.inc"
#INCLUDE "TabDDT.inc"
%IDC_TAB  = 1000
%IDLABEL1 = 1

    GLOBAL hDlg AS LONG
    GLOBAL hTab AS LONG
    GLOBAL hTabDlg1 AS LONG
    GLOBAL hTabDlg2 AS LONG
    GLOBAL hTabDlg3 AS LONG
    GLOBAL point AS POINTAPI
    GLOBAL last_point AS POINTAPI
    GLOBAL hpen AS LONG
    GLOBAL hDc AS LONG
    GLOBAL DefaultTabProc AS LONG

DECLARE CALLBACK FUNCTION MainDlgProc
DECLARE FUNCTION TabSubClassProc (BYVAL hWnd AS LONG, BYVAL wMsg AS LONG, BYVAL wParam AS LONG, BYVAL lParam AS LONG) AS LONG

FUNCTION PBMAIN
    LOCAL th AS TABHDR
    LOCAL TEXT AS STRING

    ' Main dialog
    DIALOG NEW 0, "DDT - Tab Example",,,400, 300, %WS_SYSMENU OR %WS_MINIMIZEBOX OR %DS_CENTER TO hDlg
CONTROL ADD LABEL, hDlg,%IDLABEL1,"-------- ",5,5,60,12,0

    ' Tab control
    hTab = TabCtrl(hDlg, %IDC_TAB, 20, 20, 300, 250)
    ' Tab - dialog 1
    DIALOG NEW hTab, "Tab 1",,,400, 300, %WS_CHILD OR %WS_VISIBLE  TO hTabDlg1
    ' Tab - dialog 2
    DIALOG NEW hTab, "Tab 2",,,400, 300, %WS_CHILD OR %WS_VISIBLE TO hTabDlg2
    CONTROL ADD LABEL, hTabDlg2, -1, "This is Tab 2", 5,5,50,14
    ' Tab - dialog 3
    DIALOG NEW hTab, "Tab 3",,,400,300, %WS_CHILD OR %WS_VISIBLE TO hTabDlg3
    CONTROL ADD BUTTON, hTabDlg3, 100, "A button",50,50, 90,90
    th.lID = %IDC_TAB
    th.cDialogs = 3

    th.DlgHdr(0).hTabDlg       = hTabDlg1
    th.DlgHdr(0).lpfnCallback  = CODEPTR(cbTab1)

    th.DlgHdr(1).hTabDlg       = hTabDlg2
    th.DlgHdr(1).lpfnCallback  = CODEPTR(cbTab2)

    th.DlgHdr(2).hTabDlg       = hTabDlg3
    th.DlgHdr(2).lpfnCallback  = CODEPTR(cbTab3)

    InitTabControl hDlg, th

    DIALOG SHOW MODAL hDlg CALL MainDlgProc

END FUNCTION

CALLBACK FUNCTION MainDlgProc
    
    SELECT CASE CBMSG
        CASE %WM_INITDIALOG
        DefaultTabProc = SetWindowLong(hTabDlg2, %GWL_WNDPROC, CODEPTR(TabSubClassProc))

        CASE %WM_NOTIFY
            OnTabNotify CBHNDL, CBLPARAM
      END SELECT

END FUNCTION

CALLBACK FUNCTION cbTab1
    SELECT CASE CBMSG
        CASE %WM_INITDIALOG
        CASE %WM_COMMAND
            SELECT CASE LOWRD(CBWPARAM)
           END SELECT
  END SELECT

END FUNCTION


CALLBACK FUNCTION cbTab2
  SELECT CASE CBMSG
         CASE %WM_INITDIALOG
         CASE %WM_COMMAND
              SELECT CASE LOWRD(CBWPARAM)
              END SELECT
  END SELECT

END FUNCTION

CALLBACK FUNCTION cbTab3
  SELECT CASE CBMSG
         CASE %WM_INITDIALOG
         CASE %WM_COMMAND
              SELECT CASE LOWRD(CBWPARAM)
              END SELECT
  END SELECT

END FUNCTION


FUNCTION TabSubClassProc (BYVAL hWnd AS LONG, BYVAL wMsg AS LONG, _
    BYVAL wParam AS LONG, BYVAL lParam AS LONG) EXPORT AS LONG
         LOCAL  ps     AS PAINTSTRUCT
        IF wMsg= %WM_SHOWWINDOW THEN
           BEEP
        Last_Point.x=-1
        Last_Point.y=-1
        END IF
        IF wMsg= %WM_PAINT THEN
        hdc = BeginPaint(hWnd, ps)
        hpen = CreatePen (%PS_SOLID,1,RGB(255,255,255))
        SelectObject hDC,hpen
        SetROP2 hDC, %R2_COPYPEN
        ''Draw graph here
        MoveTo hDC, 20,200
        LineTo hDC, 200,300
        MoveTo hDC, 300,50
        LineTo hDC, 50,50
        ''Draw vertical scrolling line here
        SetROP2 hDC, %R2_XORPEN
        MoveTo hDC, LAST_POINT.X,0
        LineTo hDC, LAST_POINT.X,350
        MoveTo hDC, POINT.X,0
        LineTo hDC, POINT.X,350

        DeleteObject hpen
        EndPaint hWnd, ps
        Last_Point=Point
        END IF

      IF wMsg= %WM_MOUSEMOVE THEN
        Point.X = LOWRD(lParam)
'        Point.Y = HIWRD(lParam)
        InvalidateRect hWnd, BYVAL 0, %FALSE
        UpdateWindow hWnd
        TEXT$="X: "+STR$(POINT.X)+"  Y: "+STR$(POINT.Y)
        CONTROL SET TEXT hdlg,%IDLABEL1, TEXT$
         ELSE
          FUNCTION = CallWindowProc(DefaultTabProc, hWnd, wMSg, WParam, Lparam)
END IF
END FUNCTION

Code:

'------- TabDDT.inc ---------------
'----------------------------------
' DDT Tab Control
' Peter Stephensen 2000
'----------------------------------
%TRUE=1
#IF NOT %DEF(%TAB_DLGMAX)
    %TAB_DLGMAX = 10                ' Maximal number of tab items
#ENDIF

#IF NOT %DEF(%TAB_LINES)
    %TAB_LINES = 2                  ' Number of lines in Tab control. Set this to 2
#ENDIF                              ' if multiline-style is used

TYPE DLGHDR
    hTabDlg AS LONG
    lpfnCallback AS LONG
END TYPE

TYPE TABHDR
    lID AS LONG                     ' Integer ID for Tab Control
    cDialogs AS LONG                ' Number of dialogs
    DlgHdr(%TAB_DLGMAX) AS DLGHDR   ' Dialogs
END TYPE

DECLARE SUB TabDisplay(hDlg AS LONG,TabID AS LONG,newTab AS LONG)

GLOBAL pth AS TABHDR PTR

FUNCTION TabCtrl(BYVAL hDlg AS LONG, BYVAL ID AS LONG, BYVAL x AS LONG, BYVAL y AS LONG, BYVAL xx AS LONG, BYVAL yy AS LONG) AS LONG

    LOCAL hTab AS LONG

    IF hDlg = 0 THEN EXIT FUNCTION
    CONTROL ADD "SysTabControl32", hDlg, ID, "", x, y, xx, yy, %WS_CHILD OR %WS_VISIBLE
    CONTROL HANDLE hDlg, ID TO hTab

    FUNCTION = hTab

END FUNCTION

FUNCTION InitTabControl(hDlg AS LONG, th AS TABHDR) AS LONG

    LOCAL tie AS TC_ITEM
    LOCAL rcTab AS RECT
    LOCAL i AS LONG
    LOCAL hInst AS LONG
    LOCAL hWndTab AS LONG
    LOCAL zBuffer AS ASCIIZ*128

    InitCommonControls

    pth = LocalAlloc(%LPTR, SIZEOF(@pth))

    hInst = GetModuleHandle(BYVAL 0)
    hWndTab = GetDlgItem(hDlg,th.lID)

    GetClientRect hwndTab,rcTab

    ' Add a tab for each of the child dialog boxes.
    FOR i = 0 TO th.cDialogs-1
        tie.mask = %TCIF_TEXT OR %TCIF_IMAGE
        tie.iImage = -1
        GetWindowText th.DlgHdr(i).hTabDlg, zBuffer, 128
        tie.pszText = VARPTR(zBuffer)
        TabCtrl_InsertItem hwndTab, i, tie

        MoveWindow th.DlgHdr(i).hTabDlg, _
                   4, _
                   %TAB_LINES*23, _
                   rcTab.nRight-rcTab.nLeft-11, _
                   rcTab.nBottom-rcTab.nTop-%TAB_LINES*23-3, _
                   %TRUE
    NEXT i

    @pth = th
    TabDisplay hDlg, th.lID, 0

END FUNCTION

SUB TabDisplay(hDlg AS LONG,TabID AS LONG, TabIndex AS LONG)

    STATIC PrevTabIndex AS LONG
    LOCAL i AS LONG

    IF PrevTabIndex THEN
        ShowWindow PrevTabIndex, %SW_HIDE
    END IF

    IF pth = 0 THEN EXIT SUB

    ShowWindow @pth.DlgHdr(TabIndex).hTabDlg, %SW_SHOW
    PrevTabIndex = @pth.DlgHdr(TabIndex).hTabDlg

END SUB

SUB OnTabNotify (BYVAL hDlg AS LONG, BYVAL lParam AS LONG )

    LOCAL lpNmh   AS NMHDR PTR

    IF pth = 0 THEN EXIT SUB

    lpNmh = lParam
    SELECT CASE @lpNmh.Code
    CASE %TCN_LAST TO %TCN_FIRST
        SELECT CASE @lpNmh.idFrom
        CASE @pth.lID
            SELECT CASE @lpNmh.Code
            CASE %TCN_SELCHANGE
                TabDisplay hDlg, @pth.lID, TabCtrl_GetCurSel(GetDlgItem(hDlg,@pth.lID))
            END SELECT
        END SELECT
    END SELECT

END SUB

Do you see a problem with TabDDT.Inc (courtesy of Peter Stephensen 2000, thank you Peter) that causes the cbtab(1,2,3) functions not to work?
Also, when using BeginPaint() and EndPaint(), is it necessary to DeleteObject for any pens created and ReleaseDC?
When creating new graphs/displays for the other tab pages,
would you recommend setting up seperate subclass functions to handle this via:

Code:

 
DefaultTabProc1 = SetWindowLong(hTabDlg1, %GWL_WNDPROC, CODEPTR(TabSubClassProc1))
DefaultTabProc2 = SetWindowLong(hTabDlg2, %GWL_WNDPROC, CODEPTR(TabSubClassProc2))
DefaultTabProc3 = SetWindowLong(hTabDlg3, %GWL_WNDPROC, CODEPTR(TabSubClassProc3))

Or is there a better way?

Semen, I like your code format better and will probably switch. It would be better for me to learn how tab controls work rather than rely on an Inc file. Will keep and study your example.

Thank you, Lance and Semen,
Todd Wasson

[This message has been edited by Todd Wasson (edited May 28, 2000).]

**Lance Edmonds** · 28 May 2000, 10:38 PM

Also, when using BeginPaint() and EndPaint(), is it necessary to DeleteObject for any pens created and ReleaseDC?

Definitely! You should save the initial handle that is returned from the first SelectObject() call (the handle to the "existing" object), and restore it before terminating your %WM_PAINT handler.
Also, you cannot delete any object that is still selected into a Device Context - the following psuedocode example demonstrates how to correctly handle the dynamic creation and destruction of GDI objects:

Code:

'psuedocode
CASE %WM_PAINT
  hDC = BeginPaint(...)
  hBrush = CreateBrushIndirect(...)
  hBrushOld = SelectObject(hDC, hBrush)
  ...drawing code
  DeleteOnject SelectObject(hDC, hBrushOld)
  EndPaint <params>

When creating new graphs/displays for the other tab pages, would you recommend setting up seperate subclass functions to handle this via:

Subclassing it not usually required at all for this type of task... just a callback for the modeless dialog should be sufficient - it is all I've ever needed to do.

I'm not at my DEV PC to run your code, but a quick look reveals that your code does not have a message pump for the child dialogs, so the events for these dialogs are never dispatched.

The correct way to handle this would work like this:
1. Create the parent dialog, and the tab control as a child control to that dialog. The dialog should have the extended %WS_EX_CONTROLPARENT style.
2. Create the child (modeless) dialogs as children of the main dialog, NOT the tab control. These dialogs should have the %DS_CONTROL style.
3. Use a DIALOG SHOW MODELESS statement for each of the child dialogs, and then hide each one with DIALOG SET STATE (or is it DIALOG SHOW STATE, I forget)
4. Use DIALOG SHOW MODAL to launch the main dialog.
5. In the dialog handler for the main dialog, process %WM_INITDIALOG and use PostMessage CBHNDL,%WM_USER + 999,0,0 to post a user-defined message to itself.
6. Process %WM_USER + 999& and execute a DIALOG DOEVENTS message loop which should run until the child modeless dialogs are all destroyed. This means that this event handler should run all the time, but the callback will still be able to process other messages normally.

The message pump for the modeless dialogs should look something like this:

Code:

SELECT CASE CBMSG
CASE %WM_INTIDIALOG
  ... general init code goes here.
  PostMessage CHNDL, %WM_USER+999, 0, 0
  EXIT FUNCTION
CASE %WM_USER + 999
  DO
    DIALOG DOEVENTS to nModelessCount& ' (check the syntax here... this is off the top of my head!)
  LOOP UNTIL nModelessCount& = 0
  EXIT FUNCTION

The reason for using the custom message to kick the message pump off ensures that the pump's operation does not affect the operation of normal messages that the callback can process.
I hope this helps. Tab controls are a challenge, but forgetting the message pump for modeless dialogs is a common mistake.

There is another approach to this whole tab control application - simply use modeless dialogs for everything, and place the message pump in the main (PBMAIN) code.

if this is a better choice for you, then the process would work like this:
1. Create the parent dialog, and the tab control as a child control to that dialog. The dialog should have the extended %WS_EX_CONTROLPARENT style.
2. Create the child (modeless) dialogs as children of the main dialog, NOT the tab control. These dialogs should have the %DS_CONTROL style.
3. Use a DIALOG SHOW MODELESS statement for each of the child dialogs, and then hide each one with DIALOG SET STATE (or is it DIALOG SHOW STATE, I forget)
4. Use DIALOG SHOW MODELESS to launch the main dialog.
5. start the message pump right here in PBMAIN.

Code:

'psuedocode
FUNCTION PBMAIN()
  DIALOG NEW 0,..., to hDlg
  CONTROL ADD "thetabcontrolclassname",..., to hTab
  DIALOG NEW hDlg,..., to hTabPage1
  DIALOG NEW hDlg,..., to hTabPage2
  DIALOG NEW hDlg,..., to hTabPage3
  DIALOG SHOW MODELESS hTabPage1 CALL ChildTabCallback1
  DIALOG SHOW MODELESS hTabPage2 CALL ChildTabCallback2
  DIALOG SHOW MODELESS hTabPage3 CALL ChildTabCallback3
  DIALOG SHOW MODELESS hDlg CALL ParentCallback
  DO
    DIALOG DOEVENTS To nModelessCOunt&
  LOOP UNTIL nModelessCount& = 0
END FUNCTION

That lot should keep you going for a while!

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

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Tab controls --Subclassing

Tab controls --Subclassing

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