How to: Accept files dropped from File Explorer

Let users drag documents, images, or folders from File Explorer onto a grid record or a tree node, and store them the way your application needs: as records, as paths in a field, or as copies in a folder.

Requires WKL Forms Object Library 1.57 or later.

With AllowFileDrop = True, WklGrid, WklTreeList, WklGantt, and WklTreeView accept files from File Explorer. While the user drags, FileDragOver reports each new target and lets you reject it with Cancel; after the drop, FileDrop reports the full paths, the key of the target record or node, and the position. The control doesn't write anything itself: your code in FileDrop decides what happens to the files, and Requery then shows the new records.

A grid named grdDocuments shows the current customer's records from tblDocuments (ID AutoNumber, CustomerID, FileName, FilePath). Dropped files become records for that customer; folders are rejected while dragging.

Private Sub Form_Load()
    Me!grdDocuments.Object.AllowFileDrop = True    ' or in the designer: page Behavior, card Files from Explorer
End Sub
 
Private Sub grdDocuments_FileDragOver(ByVal Files As Variant, ByVal TargetKey As Variant, _
        ByVal Position As Long, Cancel As Integer)
    Dim path As Variant
    For Each path In Files
        If (GetAttr(path) And vbDirectory) = vbDirectory Then Cancel = True: Exit Sub
    Next
End Sub
 
Private Sub grdDocuments_FileDrop(ByVal Files As Variant, ByVal TargetKey As Variant, ByVal Position As Long)
    Dim path As Variant
    For Each path In Files
        CurrentDb.Execute "INSERT INTO tblDocuments (CustomerID, FileName, FilePath) VALUES (" & Me!ID & ", '" & _
            Replace(Mid$(path, InStrRev(path, "\") + 1), "'", "''") & "', '" & Replace(path, "'", "''") & "')", dbFailOnError
    Next
    Me!grdDocuments.Object.Requery
End Sub

• Arguments: Files is a zero-based array of full paths (use For Each or UBound). TargetKey is the key of the record or node under the mouse pointer, or Null below the last one, on a group row, and on the new-record row. Position is a WklDropPosition (wdpBefore, wdpAfter, wdpInside), so a tree can place a file before, after, or below a node.
• Keep FileDragOver short. File Explorer waits for it while the user drags. FileDrop runs after the drop is complete, so it can show messages, copy files, or prompt the user.
• Files only. Text from Word, an email message from Outlook, or the control's own dragged nodes aren't files; the control rejects them without raising an event. To accept email messages or attachments, save them to a folder first.
• Form view only. In Design view and in reports, the control doesn't accept files.
• Event declarations: declare Position as Long or as WklDropPosition (which requires a reference to the WKL Forms Object Library); Cancel must be passed by reference (Cancel As Integer).
• The setting is saved with the form. It doesn't change AllowDragDrop, which moves nodes within a tree.

• API reference: WklGrid.AllowFileDrop, FileDragOver, FileDrop
• API reference: WklTreeView.AllowFileDrop
• WklGrid overview, WklTreeView overview