How can I drag & drop a file from the shell? [duplicate] - delphi

Question

This question already has answers here:
Cross-application drag-and-drop in Delphi
(2 answers)
Closed 8 years ago.
I am trying to drag and drop a video file (like .avi) from desktop But ı can not take it to the my program.But when ı try to drag and drop inside my program it works fine.For ex: I have an edittext and a listbox inside my pro and ı can move text that inside edittext to listbox.I could not get what is the difference ??
I take the video using openDialog.But ı wanna change it with drag and drop.
procedure TForm1.Button1Click(Sender: TObject);
begin
if OpenDialog1.Execute then
begin
MediaPlayer1.DeviceType:=dtAutoSelect;
MediaPlayer1.FileName := OpenDialog1.FileName;
Label1.Caption := ExtractFileExt(MediaPlayer1.FileName);
MediaPlayer1.Open;
MediaPlayer1.Display:=Self;
MediaPlayer1.DisplayRect := Rect(panel1.Left,panel1.Top,panel1.Width,panel1.Height);
panel1.Visible:=false;
MediaPlayer1.Play;
end;
end;

Answer 1

Here is a simple demo how to drag&drop files from Windows Explorer into a ListBox (for Delphi XE):
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;
type
TForm1 = class(TForm)
ListBox1: TListBox;
procedure FormCreate(Sender: TObject);
procedure FormDestroy(Sender: TObject);
private
{ Private declarations }
protected
procedure WMDropFiles(var Msg: TMessage); message WM_DROPFILES;
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
uses ShellAPI;
procedure TForm1.FormCreate(Sender: TObject);
begin
DragAcceptFiles(Handle, True);
end;
procedure TForm1.FormDestroy(Sender: TObject);
begin
DragAcceptFiles(Handle, False);
end;
procedure TForm1.WMDropFiles(var Msg: TMessage);
var
hDrop: THandle;
FileCount: Integer;
NameLen: Integer;
I: Integer;
S: string;
begin
hDrop:= Msg.wParam;
FileCount:= DragQueryFile (hDrop , $FFFFFFFF, nil, 0);
for I:= 0 to FileCount - 1 do begin
NameLen:= DragQueryFile(hDrop, I, nil, 0) + 1;
SetLength(S, NameLen);
DragQueryFile(hDrop, I, Pointer(S), NameLen);
Listbox1.Items.Add (S);
end;
DragFinish(hDrop);
end;
end.

Answer 2

You can also use DropMaster from Raize software.

Answer 3

You can catch the WM_DROPFILES message.
First, set that your form will "accept" files from dragging in the FormCreate procedure:
DragAcceptFiles(Self.Handle, True);
After, declare the procedure in the desired form class:
procedure WMDropFiles(var Msg: TMessage); message WM_DROPFILES;
Finally, fill the procedure body as follows:
procedure TForm1.WMDropFiles(var Msg: TMessage);
begin
// do your job with the help of DragQueryFile function
DragFinish(Msg.WParam);
end

Answer 4

Alternatively, check out "The Drag and Drop Component Suite for Delphi" by Anders Melander. It works as-is with 32-bit and with some tweaking can be made to work with 64-bit as well (read the blog - it has been upgraded by 3rd parties).