Invalid use of AddressOf operator

[Nitesh]

Hi Guys,

This is part of my code to create a drag image of the treeview item being dragged:

Public Sub TreeView_StartDrag( _
   ByVal hWndTreeView As Long, _
   Optional ByVal x As Long = 20, _
   Optional ByVal y As Long = 20)
Dim tPoint As POINTL
Dim hItem As Long

   ' Get the selected node
   hItem = SendMessage(hWndTreeView, TVM_GETNEXTITEM, TVGN_DROPHILITE, ByVal 0&)
   
   ' Get a ImageList with the drag image
   m_lIL = SendMessage(hWndTreeView, TVM_CREATEDRAGIMAGE, 0, ByVal hItem)
   
   ' Start the image dragging
   ImageList_BeginDrag m_lIL, 0, x, y
   ImageList_DragEnter 0, 0, 0
   
   ' Start the timer
   m_lTimer = SetTimer(0, 0, 1, AddressOf pvTimerDragMove)

End Sub

Private Sub pvTimerDragMove( _
   ByVal hWnd As Long, _
   ByVal uMsg As Long, _
   ByVal idEvent As Long, _
   ByVal dwTime As Long)
Dim tPoint As POINTL
   
   ' Get the cursor position
   GetCursorPos tPoint

   ' Move the image to the new cursor position
   ImageList_DragMove tPoint.x, tPoint.y
   
End Sub

I get an invalid use of AddressOf operator on the line I have highlighted in red. Please help

[Doogle]

You can only use AddressOf to point to something in a .Bas module. pvTimerDragMove must be in a Module as opposed to a Form

[Nitesh]

Thanks Doogle,

That fixed the problem.

I am using the code from this site:

http://www.mvps.org/emorcillo/en/cod...ropimage.shtml

but it isn't creating the drag image. could someone please test this code. I would post my project but I have stored procedures for populating my treeview.

[Nitesh]

Guys, these to lines always return 0.

hItem = SendMessage(hWndTreeView, TVM_GETNEXTITEM, TVGN_DROPHILITE, ByVal 0&)
   
   ' Get a ImageList with the drag image
   m_lIL = SendMessage(hWndTreeView, TVM_CREATEDRAGIMAGE, 0, ByVal hItem)

hitem and m_lIL are always zero

[Doogle]

Have you looked at Err.LastDllError after the first sendmessage fails. It may give you a hint as to what's wrong.

[Nitesh]

Hi Doogle,

It returns 0.

[Doogle]

So it's not 'failing' in that sense, looking at the documentation for the message (http://msdn2.microsoft.com/en-us/lib...22(VS.85).aspx) the remarks say

This message will return NULL if the item being retrieved is the root node of the tree.

Perhaps that's the problem(?)

[Nitesh]

these are the values I assign to those variables:

Const TVM_CREATEDRAGIMAGE = &H1100& + 18
Const TVM_GETNEXTITEM = &H1100& + 10
Const TVGN_DROPHILITE = &H8

[Doogle]

Thpse values look ok to me. If they were incorrect I suspect you'd see a non-zero Err.LastDllError. Is the drop target the roor of the treeview?

[Nitesh]

No it isn't. Those variables need to take on a value greater than zero once the dragging begins. That doesn't happen. I'm assuming that is why no image gets created.

[Nitesh]

Hey Guys, I think I fixed it ,

I added this into my module:

Private Const TVGN_CARET = 9

and changed this line to the following:

hitem = SendMessage(hWndTreeView, TVM_GETNEXTITEM, TVGN_CARET, ByVal 0&)

seems right. Can anyone verify that I am right please.