Get OLEDrop Path

Hi,

is it possible to get drop path of OLE. i have a listview and there is file names. i ll drag and drop a file name to the desktop, in this moment can i get path of the desktop ? i ll use winsock so i can not use adding file event. i just need to get path of dropped zone.

thanks in advance.

Knowing the drop path generally isn't a big deal. The target will decide where to place the files and with Vista, this may be a virtual folder different than the target. Getting the drop path may require some serious hacking if it is possible and would be target-specific.

There is a workaround when the files are not physically on the target system which sounds like your scenario... How can you drop/transfer the files if you don't know where to transfer them to? Answer: save them to a temp path & let the target transfer from there to actual location. Another scenario are files that take time to process before dropped, like zips, don't want to prematurely unzip/process if user is going to cancel the operation, do you?

Here are two workarounds
1. Reactive. Transfer/unzip files to user's temp path. Add the files to the Data object and remove the files after drag/drop complete, whether canceled or not.
2. Proactive. Wait until the user makes a decision, then transfer/unzip the files to user's temp path and add those files to the data object.

vb Code:

' Delcarations
Private Declare Function GetKeyState Lib "user32.dll" (ByVal nVirtKey As Long) As Integer
Private Const VK_LEFT As Long = &H25
 
' sample usage, change Picture1 to your object that is being dragged
Private Sub Picture1_OLEStartDrag(Data As DataObject, AllowedEffects As Long)
    ' change effects as needed
    AllowedEffects = vbDropEffectCopy Or vbDropEffectMove
    Data.Clear
    Data.SetData , vbCFFiles ' by not actually populating data, we get the SetData event
End Sub
Private Sub Picture1_OLESetData(Data As DataObject, DataFormat As Integer)
    If GetKeyState(VK_LEFT) > -1 Then ' test for left mouse button up (user made decision)
        ' unzip/transfer files to user's temp path.
        ' else unzip/transfer files to other writable path
     
        ' now add the temp path/filenames to the data object
        ' i.e., Data.Files.Add ....
    End If
End Sub
Private Sub Picture1_OLECompleteDrag(Effect As Long)
    ' clean up the temp path/files. Remove them
    If Effect = vbDropEffectMove Then
       ' remove these from your server if you offered that option
    End If
End Sub

Here is an example of the GetTempPath API

LaVolpe,

thank you so much for your reply. if i understand well there is no way to get path of drop zone. maybe i should to use common dialog then it will be better for process.

thank you again.

I wouldn't say there is no way to get the path, but it would be target specific. What if user drops files to explorer, desktop, custom app, a remote server like an FTP, etc, etc. IMO, your app should only be responsible for making the files available, not actually doing the transfer if OLE drag/drop is being used.

If you are going to use a common dialog, then ensure you use appropriate error checking, as user can drop to unwritable paths (lacking permissions).

An ideal situation may be to support both, allow drag/drop and also allow transfer via a dialog.