HOWTO: Obtain Files Copied from Windows Explorer

• Microsoft Visual Basic Professional and Enterprise Editions for Windows, versions 5.0, 6.0

SUMMARY

When Windows Explorer is used to cut or copy files, it places information about the files in the clipboard. A Visual Basic application can read this information from the clipboard and act upon it.

MORE INFORMATION

Step by Step Example

1. Start a new Visual Basic Standard EXE project. Form1 is created by default.



2. Add a ListBox (List1) and a CommandButton (Command1) control to Form1.



3. Paste the following code into the General Declarations section of Form1:




Option Explicit

Private Const CF_HDROP = 15

Private Type POINT
    x As Long
    y As Long
End Type

Private Type DROPFILES
    pFiles As Long
    pt As POINT
    fNC As Long
    fWide As Long
End Type

Private Declare Function GlobalSize Lib "kernel32" _
   (ByVal hMem As Long) As Long
Private Declare Function GlobalLock Lib "kernel32" _
   (ByVal hMem As Long) As Long
Private Declare Function GlobalUnlock Lib "kernel32" _
   (ByVal hMem As Long) As Long

Private Declare Function OpenClipboard Lib "user32" _
   (ByVal hwnd As Long) As Long
Private Declare Function CloseClipboard Lib "user32" () As Long
Private Declare Function GetClipboardData Lib "user32" _
   (ByVal wFormat As Long) As Long

Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" _
   (Destination As Any, Source As Any, ByVal Length As Long)

Private Sub ShowFilesOnClipboard()
   Dim lHandle As Long
   Dim lpResults As Long
   Dim lRet As Long
   Dim df As DROPFILES
   Dim strDest As String
   Dim lBufferSize As Long
   Dim arBuffer() As Byte
   Dim vNames As Variant
   Dim i As Long

   If OpenClipboard(0) Then
      lHandle = GetClipboardData(CF_HDROP)
      ' If you don't find a CF_HDROP, you don't want to process anything
      If lHandle > 0 Then
         lpResults = GlobalLock(lHandle)
         
         lBufferSize = GlobalSize(lpResults)
         ReDim arBuffer(0 To lBufferSize)
         
         CopyMemory df, ByVal lpResults, Len(df)
         Call CopyMemory(arBuffer(0), ByVal lpResults + df.pFiles, _
                         (lBufferSize - Len(df)))

         If df.fWide = 1 Then
            ' it is wide chars--unicode
            strDest = arBuffer
         Else
            strDest = StrConv(arBuffer, vbUnicode)
         End If
         GlobalUnlock lHandle
         vNames = Split(strDest, vbNullChar)
         i = 0
         While Len(vNames(i)) > 0
            List1.AddItem vNames(i)
            i = i + 1
         Wend
      End If
   End If
   CloseClipboard
End Sub

Private Sub Command1_Click()
   Call ShowFilesOnClipboard
End Sub 

4. Run the project and use Windows Explorer to select and copy several files.



5. Press Command1 and note that the list of files that you copied is displayed in List1.

Additional query words:

Keywords : kbAPI kbClipboard kbSDKWin32 kbVBp kbVBp500 kbVBp600 kbGrpVB kbDSupport
Version : WINDOWS:5.0,6.0
Platform : WINDOWS
Issue type : kbhowto