[NumLock]

Код:

unit Unit1;

interface

uses
  ShellAPI,
  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 }
  public
    { Public declarations }
    procedure WMDROPFILES(var Msg: TMessage); message WM_DROPFILES;
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

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
  Drop: HDROP;
  buf: array [0..255] of Char;
  i, cnt: integer;
begin
  Drop:=Msg.WParam;
  cnt:=DragQueryFile(Drop, $0ffffffff, @buf, SizeOf(buf));
  for i:=0 to cnt-1 do
    ListBox1.Items.Add(Copy(buf, 1, DragQueryFile(Drop, i, @buf, SizeOf(buf))));
  DragFinish(Drop);
end;

end.