I am only dragging 1 file if that will simplify any.
Errors?  
Improvements?
<EDIT: I am dragging to another application, not receiving a dragged file.


<http://groups.google.com/group/borland.public.delphi.nativeapi/browse_thread/thread/3807c98996c6dc4a/906ac37701139ab8?q=How+to+automatically+drag+and+drops+a+file+onto+any+window>


or  


procedure DoDropFiles(Wnd: HWND; Files: TStringList);


var
  Size: Cardinal;
  DropFiles: PDropFiles;
  Run: PChar;
  MemHandle: THandle;
  I: Integer;


begin
  // first determine size of string buffer we have to allocate
  Size := 0;
  for I := 0 to Files.Count - 1 do
  begin
    // number of characters per string (as ANSI) plus one #0 terminator
    Inc(Size, Length(Files[I]) + 1);
  end;
  if Size > 0 then
  begin

    Inc(Size, 1 + SizeOf(TDropFiles));
    // allocate globally accessible memory
    MemHandle := GlobalAlloc(GHND or GMEM_SHARE, Size);
    DropFiles := GlobalLock(MemHandle);
    // fill the header
    with DropFiles^ do
    begin

    end;
    // and finally the file names
    Run := Pointer(DropFiles);
    Inc(Run, SizeOf(TDropFiles));
    for I := 0 to Files.Count - 1 do
    begin
      StrPCopy(Run, Files[I]);
//      Inc(Run, Length(Files[I]));
      Inc(Run, Length(Files[I])+1)
    end;
    // put a final #0 character at the end
    Run^ := #0;
    // release the lock we have to the memory,...
    GlobalUnlock(MemHandle);
    // ...do the message...
//    SendMessage(Wnd, WM_DROPFILES, MemHandle, 0);
    PostMessage(Wnd, WM_DROPFILES, MemHandle, 0);
 
    // ... and finally release the memory
    GlobalFree(MemHandle);
  end;
end;


procedure TMainForm.Button1Click(Sender: TObject);
var
  List: TStringList;
begin
  List := TStringList.Create;
  try
    List.Add('C:\Data\Test.txt');
    DoDropFiles(Handle, List);
  finally
    List.Free;
  end;
end;






Norm


Edited by: Norm Carlberg on Sep 25, 2010 6:40 AM