Here is a post from Felix Lima, a MS Suport Engineer, on Drag and Drop
in Access.
In order to do this effectively in Access, you will need to use
subclassing
and API calls. Subclassing in Access is not really recommended and may
cause significant problems. Q278379 explains some problems with
subclassing:
"Because of problems with subclassing windows after loading the
Microsoft Office Visual Basic Editor,
Microsoft highly recommends that you use Microsoft Visual Basic or
Microsoft Visual C++ to
create an ActiveX DLL, and that you then reference the DLL from your
Microsoft Access
application."
Basically, In order to successfully get this to work, you need to
subclass the window and then call the DragAcceptFiles() API. When the
user drops
files from explorer, the window is sent the WM_DROPFILES message. This
can be accomplished in Access by first creating a VB dll and then
calling
the dll from Access.
I was able to create a VB 6 dll which can be referenced in Access to
successfully get the file path from windows explorer to a textbox on an
access form. (It is a modification of a post by Stoil Marinov in
comp.lang.basic.visual 19/11/1999):
Here are the steps I took:
a) Create a VB6 dll with a module (basDragDrop) and a class
(clsDragDrop)
b) Add the following code to the basDragDrop module:
Option Compare Text
Option Explicit
Public CDrag As CDragDrop
Public lpPrevWndProc As Long
Public Const GWL_WNDPROC = (-4)
Public Const WM_DROPFILES = &H233
Public Const GetNumOfFiles = &HFFFF
Public Declare Function CallWindowProc Lib "user32" Alias _
"CallWindowProcA" (ByVal lpPrevWndFunc As Long, _
ByVal hWnd As Long, _
ByVal Msg As Long, _
ByVal wParam As Long, _
ByVal lParam As Long) As Long
Public Declare Function SetWindowLong Lib "user32" Alias _
"SetWindowLongA" (ByVal hWnd As Long, _
ByVal nIndex As Long, _
ByVal dwNewLong As Long) As Long
Public Declare Sub DragAcceptFiles Lib "shell32.dll" _
(ByVal hWnd As Long, _
ByVal fAccept As Long)
Public Declare Sub DragFinish Lib "shell32.dll" _
(ByVal hDrop As Long)
Public Declare Function DragQueryFile Lib "shell32.dll" _
Alias "DragQueryFileA" (ByVal hDrop As Long, _
ByVal lFile As Long, _
ByVal lpFileName As String, _
ByVal cbLen As Long) As Long
Public Function WindowProc(ByVal hWnd As Long, ByVal Msg As Long, ByVal
wp
As Long, ByVal lp As Long) As Long
If Msg = WM_DROPFILES Then
'Files have been dropped
CDrag.AcceptDroppedFiles wp
Else
WindowProc = CallWindowProc(lpPrevWndProc, hWnd, Msg, wp, lp)
End If
End Function
c) Add the following code CDragDrop:
Option Compare Text
Option Explicit
Private frm As Object
Private txt As Object
Public Property Set Form(frmIn As Object)
Set frm = frmIn
End Property
Public Property Set textbox(txtin As Object)
Set txt = txtin
End Property
Public Sub SubClassHookForm()
Call DragAcceptFiles(frm.hWnd, 1)
lpPrevWndProc = SetWindowLong(frm.hWnd, GWL_WNDPROC, _
AddressOf WindowProc)
Set CDrag = Me
End Sub
Public Sub SubClassUnHookForm()
Call SetWindowLong(frm.hWnd, GWL_WNDPROC, lpPrevWndProc)
Call DragAcceptFiles(frm.hWnd, 0)
End Sub
Sub AcceptDroppedFiles(hDrop As Long)
Dim lNumOfFiles As Long
Dim lReturn As Long
Dim sFilename As String
Dim lm As Long
'Get the number of dropped files
lNumOfFiles = DragQueryFile(hDrop, GetNumOfFiles, 0&, 0)
For lm = 0 To lNumOfFiles
'Allocate buffer for the name of the file
sFilename = String$(257, Chr$(0))
'Get the name of the file
lReturn = DragQueryFile(hDrop, lm, sFilename, Len(sFilename))
'Add the file name to the list
If lReturn > 0 Then
txt.Text = txt.Text & Left$(sFilename, lReturn) & vbCrLf
End If
Next lm
'Tell Windows to free the memory allocated to store the dropped files
DragFinish hDrop
End Sub
c) Compile the dll in VB
d) Add the following to a form in Access that has a textbox called
Text1
and a reference to the compiled dll above:
Option Compare Database
Option Explicit
Dim CDrag As New CDragDrop
Private Sub Form_Load()
'Subclass the form
Set CDrag.TextBox = Me.Text1
Set CDrag.Form = Me
CDrag.SubClassHookForm
End Sub
Private Sub Form_Unload(Cancel As Integer)
'UnSubclass the form
CDrag.SubClassUnHookForm
Set CDrag.Form = Nothing
Set CDrag.TextBox = Nothing
Set CDrag = Nothing
End Sub
HTH
Félix Lima
Microsoft Online Support Engineer
This posting is provided "AS IS" with no warranties, and confers no
rights.
Get Secure! -
www.microsoft.com/security
--
HTH
Stephen Lebans
http://www.lebans.com
Access Code, Tips and Tricks
Please respond only to the newsgroups so everyone can benefit.
"WindAndWaves" <ac****@ngaru.com> wrote in message
news:3n******************@news.xtra.co.nz...
Hi everyone,
Has anyone got any experience with drop and drag in Access?
I would like to make a calendar style form where my users can drop and
drag appointments....
I am using Access 2003 and I have access to .net and the like, but I
would really like to keep it simple.
Thank you
Nicolaas
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