Treeview Problem

[LRantanen]

Hi all,

I hope I don't feel like an idiot after this question.

I am trying to learn how to use tree view control. I have code which creates the window nicely. After that I try to insert just the root item using following two procedures, but I only manage to produce GPF.

Can somebody just by looking at this code give any hints where the problem might be? I don't like posting the original code because it is quite extensive.

Variables not declared in these produres are globals.

TIA
Lasse Rantanen
[email protected]

SUB TV_InitTreeView (hInst AS LONG, hWndTree AS LONG)

    LOCAL szText    AS ASCIIZ*%MAX_CATEGORY

    CALL LoadString(hInst, %IDS_NETWORK, szText, %MAX_CATEGORY)

    hTPrev = %TVI_ROOT
    iImage = idxNetwork
    hTParent = %NULL
    iSelect = idxNetwork

    hTRoot = TV_AddOneItem(BYVAL VARPTR(szText),BYVAL  hwndTree, -1)

    hTParent = hTRoot
    hTPrev = %TVI_FIRST
    iImage = idxNic
    iSelect = idxSelect

END SUB

FUNCTION TV_AddOneItem( lpszText AS ASCIIZ PTR , hwndTree AS LONG, index AS INTEGER) AS LONG

    LOCAL hItem AS LONG
    LOCAL tvI 	AS TV_ITEM_UNION
    LOCAL tvIns AS TV_INSERTSTRUCT

    tvI.item.mask = %TVIF_TEXT OR %TVIF_IMAGE OR %TVIF_SELECTEDIMAGE OR %TVIF_PARAM
    tvI.item.pszText = lpszText
    tvI.item.cchTextMax = LEN(@lpszText)
    tvI.item.iImage = iImage
    tvI.item.iSelectedImage = iSelect
    tvI.item.lParam = index

    tvIns.item = tvI
    tvIns.hInsertAfter = hTPrev
    tvIns.hParent = hTParent
    hItem = SendMessage(hwndTree, %TVM_INSERTITEM, 0, VARPTR(tvIns)) '<-- GPF here

    FUNCTION = hItem

END FUNCTION

[Eric Pearson]

Lasse --

I don't see anything that is obviously wrong. What does the TV_ITEM_UNION structure look like? Unless you're doing something unusual it would be much easier for you to get rid of it and do this...

FUNCTION TV_AddOneItem( lpszText AS ASCIIZ PTR , hwndTree AS LONG, index AS INTEGER) AS LONG
    LOCAL tvIns AS TV_INSERTSTRUCT
    tvIns.item.mask = %TVIF_TEXT OR %TVIF_IMAGE OR %TVIF_SELECTEDIMAGE OR %TVIF_PARAM
    tvIns.item.pszText = lpszText
    tvIns.item.cchTextMax = LEN(@lpszText)
    tvIns.item.iImage = iImage
    tvIns.item.iSelectedImage = iSelect
    tvIns.item.lParam = index
    tvIns.hInsertAfter = hTPrev
    tvIns.hParent = hTParent
    FUNCTION = SendMessage(hwndTree, %TVM_INSERTITEM, 0, VARPTR(tvIns))
END FUNCTION

Other than that, I'd suggest starting with an easier addition. Forget the images and lParam stuff until you can get it to add a simple text item to the tree. Less to troubleshoot. And this would be more "traditional" and (IMO) easier to troubleshoot...

FUNCTION TV_AddOneItem( lpszText AS [b]ASCIIZ[/b] , hwndTree AS LONG, index AS INTEGER) AS LONG
    '(etc)
    tvIns.item.pszText = VARPTR(lpszText)
    tvIns.item.cchTextMax = LEN(lpszText)

For that matter, the .ccTextMax element is ignored when you are setting a tree item. Simplify, simplify...

-- Eric


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Perfect Sync: Perfect Sync Development Tools
Email: mailto:[email protected][email protected]</A>

[LRantanen]

Thank you response Eric. Tried to do what you suggested, but I still can't make it work.

Here are the declarations from my COMMCTRL.INC (dated Dec. 10, 1999 )

UNION TV_ITEM_UNION
itemex AS TVITEMEX
item AS TV_ITEM
END UNION

TYPE TV_INSERTSTRUCT
hParent AS DWORD
hInsertAfter AS DWORD
item AS TV_ITEM_UNION
END TYPE

FUNCTION TreeView_InsertItem (BYVAL hWnd AS LONG, lpis AS TV_INSERTSTRUCT) AS DWORD
FUNCTION = SendMessage(hWnd, %TVM_INSERTITEM, 0, VARPTR(lpis))
END FUNCTION

If I change the declaration of TV_INSERTSTRUCT to what API docs say (member item has type TV_ITEM) the result is still the same.

I stripped away all the irrelevant code from the program I'm working on and attached resulting code hoping somebody has time to look at it and possibly find out why it does not work. The really embarrassing thing is that the C code I'm using as an example, works OK. It must be something rather simple I'm missing here.

TIA
Lasse Rantanen
[email protected]

' Eliminate unnecessary macros
%NOANIMATE = 1
%NODRAGLIST = 1
%NOHEADER = 1
'%NOIMAGELIST = 1
'%NOLISTVIEW = 1
%NOTABCONTROL = 1
%NOTRACKBAR = 1
'%NOTREEVIEW = 1
%NOUPDOWN = 1

$DIM ALL
$COMPILE EXE
$OPTION VERSION4

$INCLUDE "WIN32API.INC"
$INCLUDE "COMMCTRL.INC"

'==========================================================
'//* Constants
%ID_TREEVIEW        = 1003
%MAX_CATEGORY       = 32

'//* structures
TYPE tagLISTINFO
    hInst           AS LONG
    hWndMain        AS LONG
    hWndTreeView    AS LONG
END TYPE

'//* Globals
GLOBAL g_ListInfo   AS tagLISTINFO
GLOBAL hTRoot AS DWORD
GLOBAL hTPrev AS DWORD
GLOBAL hTParent AS DWORD

'//* Function prototypes
DECLARE FUNCTION InitInstance(BYVAL hInstance AS LONG, BYVAL iCmdShow AS LONG) AS INTEGER
DECLARE FUNCTION InitApplication(BYVAL hInstance AS LONG) AS INTEGER
DECLARE FUNCTION CreateControls(BYVAL hWndParent AS LONG) AS INTEGER
DECLARE FUNCTION TV_CreateTreeView ( hWndParent AS LONG, hInst AS LONG) AS LONG
DECLARE FUNCTION TV_AddOneItem( lpszText AS ASCIIZ PTR , hwndTree AS LONG, index AS INTEGER) AS DWORD

'==========================================================
FUNCTION WINMAIN (BYVAL hInstance     AS LONG, _
                  BYVAL hPrevInstance AS LONG, _
                  lpCmdLine           AS ASCIIZ PTR, _
                  BYVAL iCmdShow      AS LONG) AS LONG

    LOCAL Msg   AS tagMSG

    InitApplication hInstance
    InitInstance hInstance, iCmdShow
    WHILE (GetMessage(Msg, %NULL, 0, 0) > 0)
        TranslateMessage Msg
        DispatchMessage Msg
    WEND
    FUNCTION = Msg.wParam
END FUNCTION

'==========================================================
FUNCTION InitApplication(BYVAL hInstance AS LONG) AS INTEGER

    LOCAL wcNetwork     AS WndClassEx
    LOCAL szMenuName    AS ASCIIZ * 80
    LOCAL szClassName   AS ASCIIZ * 80

    szMenuName  = "NetworkMenu"
    szClassName = "NetworkWClass"

    wcNetwork.cbSize           = SIZEOF(wcNetwork)
    wcNetwork.style            = %CS_HREDRAW OR %CS_VREDRAW
    wcNetwork.lpfnWndProc      = CODEPTR( WndProc )
    wcNetwork.cbClsExtra       = 0
    wcNetwork.cbWndExtra       = 0
    wcNetwork.hInstance        = hInstance
    wcNetwork.hIcon            = LoadIcon(hInstance, BYVAL %NULL)
    wcNetwork.hCursor          = LoadCursor(%NULL, BYVAL %IDC_ARROW)
    wcNetwork.hbrBackground    = GetStockObject(%LTGRAY_BRUSH )
    wcNetwork.lpszMenuName     = VARPTR( szMenuName )
    wcNetwork.lpszClassName    = VARPTR( szClassName )
    wcNetwork.hIconSm          = LoadIcon( hInstance, BYVAL %NULL)

    FUNCTION = RegisterClassEx(wcNetwork)

END FUNCTION

'==========================================================
FUNCTION InitInstance(BYVAL hInstance AS LONG, BYVAL iCmdShow AS LONG) AS INTEGER

    LOCAL hWnd AS LONG

    g_ListInfo.hInst = hInstance
    g_ListInfo.hWndMain = CreateWindow( "NetworkWClass", _
                                        "Treeview Test", _
                                        %WS_OVERLAPPEDWINDOW, _
                                        GetSystemMetrics ( %SM_CXSCREEN )/4, _
                                        GetSystemMetrics ( %SM_CYSCREEN )/4, _
                                        GetSystemMetrics ( %SM_CXSCREEN )/2, _
                                        GetSystemMetrics ( %SM_CYSCREEN )/2, _
                                        %NULL, _
                                        %NULL, _
                                        hInstance, _
                                        BYVAL %NULL)
    ShowWindow g_ListInfo.hWndMain, iCmdShow
    UpdateWindow g_ListInfo.hWndMain
    FUNCTION=%TRUE
END FUNCTION

'==========================================================
FUNCTION WndProc (BYVAL hWnd AS LONG, BYVAL wMsg AS LONG, _
                  BYVAL wParam AS LONG, BYVAL lParam AS LONG) AS LONG
    SELECT CASE wMsg
        CASE %WM_CREATE
            CreateControls hWnd
            FUNCTION = %NULL
            EXIT FUNCTION
        CASE %WM_DESTROY
            PostQuitMessage 0
            FUNCTION = %NULL
            EXIT FUNCTION
    END SELECT
    FUNCTION = DefWindowProc(hWnd, wMsg, wParam, lParam)
END FUNCTION

'==========================================================
FUNCTION CreateControls(BYVAL hWndParent AS LONG) AS INTEGER

    InitCommonControls
    g_ListInfo.hWndTreeview = TV_CreateTreeview(hWndParent, g_ListInfo.hInst)
    IF g_ListInfo.hWndTreeview = 0 THEN
        FUNCTION = %FALSE
        EXIT FUNCTION
    END IF
    FUNCTION = %TRUE
END FUNCTION

'==========================================================
FUNCTION TV_CreateTreeView ( hWndParent AS LONG, hInst AS LONG) AS LONG

    LOCAL hwndTree      AS LONG
    LOCAL rcl           AS RECT
    LOCAL iLeft         AS INTEGER
    LOCAL iTop          AS INTEGER
    LOCAL iWidth        AS INTEGER
    LOCAL iHeight       AS INTEGER

    GetClientRect hWndParent, BYVAL VARPTR(rcl)
    iLeft = 0
    iTop = 0
    iWidth = (rcl.nRight - rcl.nLeft)/4
    iHeight = rcl.nBottom - rcl.nTop
    hwndTree = CreateWindowEx(  %WS_EX_CLIENTEDGE, _
                                $WC_TREEVIEW , _
                                "",_
                                %WS_VISIBLE OR %WS_CHILD OR %WS_BORDER OR %TVS_HASLINES OR _
                                %TVS_HASBUTTONS OR %TVS_LINESATROOT , _
                                iLeft, iTop, iWidth, iHeight, _
                                hWndParent, _
                                %ID_TREEVIEW, _
                                hInst, _
                                BYVAL %NULL )
    CALL TV_InitTreeView(hInst, hwndTree)
    FUNCTION = hWndTree
END FUNCTION

'==========================================================
SUB TV_InitTreeView (hInst AS LONG, hWndTree AS LONG)

    LOCAL szText    AS ASCIIZ*%MAX_CATEGORY

    szText = "Root Item"
    hTPrev = %TVI_ROOT
    hTParent = %NULL
    hTRoot = TV_AddOneItem(BYVAL VARPTR(szText),BYVAL  hwndTree, -1)
    hTParent = hTRoot
    hTPrev = %TVI_FIRST
END SUB

'==========================================================
FUNCTION TV_AddOneItem( lpszText AS ASCIIZ PTR , hwndTree AS LONG, index AS INTEGER) AS DWORD

    LOCAL hItem AS DWORD
    LOCAL tvI AS TV_ITEM_UNION
    LOCAL tvIns AS TV_INSERTSTRUCT

    tvIns.item.mask = %TVIF_TEXT OR %TVIF_IMAGE OR %TVIF_SELECTEDIMAGE OR %TVIF_PARAM
    tvIns.item.pszText = lpszText
    tvIns.item = tvI
    tvIns.hInsertAfter = hTPrev
    tvIns.hParent = hTParent
    ' Following statement GPF's
    hItem = SendMessage(hwndTree, %TVM_INSERTITEM, 0, VARPTR(tvIns))
    FUNCTION = hItem
END FUNCTION

[LRantanen]

Oh boy, I knew it was something simple.

The problem was function declaration

FUNCTION TV_AddOneItem( lpszText AS ASCIIZ PTR , hwndTree AS LONG, index AS INTEGER) AS DWORD

After changing it to

FUNCTION TV_AddOneItem( lpszText AS ASCIIZ PTR , BYVAL hwndTree AS LONG, index AS INTEGER) AS DWORD

everything works.

I don't know why these little stupid things keep haunting me.

Lasse Rantanen
[email protected]

[Eric Pearson]

Lasse --

> I don't know why these little stupid things keep haunting me.

Don't feel bad, that's a hard one to find, once you've typed it wrong. I've done it many times myself.

Maybe we should add something like this...

#PARAMETERS BYVAL

...to the PB/DLL wish list, to specify the default numeric-parameter-passing method. BYVAL is the most efficient method, so it would be nice to have a way to specify it globally.

-- Eric


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Perfect Sync: Perfect Sync Development Tools
Email: mailto:[email protected][email protected]</A>



[This message has been edited by Eric Pearson (edited February 18, 2000).]