[hitman797]

var
  Form4: TForm4;
  Directory: TDirectoryListBox;
  Drive: TDriveComboBox;
  FileList: TFileListBox;

procedure TForm4.FormCreate(Sender: TObject);
begin
  // Directory
  Directory:= TDirectoryListBox.Create(nil);
  Directory.ParentWindow:=FmxHandleToHWND(Form4.Handle);
  Directory.Visible:=False;
  Directory.FileList:=FileList;
  // Drive
  Drive:= TDriveComboBox.Create(nil);
  Drive.ParentWindow:=FmxHandleToHWND(Form4.Handle);
  Drive.Visible:=False;
  Drive.TextCase:=tcUpperCase;
  Drive.DirList:=Directory;
  // FileList
  FileList:= TFileListBox.Create(nil);
  FileList.ParentWindow:=FmxHandleToHWND(Form4.Handle);
  FileList.Visible:=False;
  //
  ListBox1.Items:= Directory.Items;
  ListBox2.Items:= FileList.Items;
  ComboBox1.Items:= Drive.Items;
end;

procedure TForm4.ComboBox1Change(Sender: TObject);
begin
  Drive.ItemIndex:= ComboBox1.ItemIndex;
end;

procedure TForm4.ListBox1ItemClick(const Sender: TCustomListBox;
  const Item: TListBoxItem);
begin
  ListBox1.BeginUpdate;
  ListBox1.Items:= Directory.Items;
  ListBox1.EndUpdate;
end;

procedure TForm4.ListBox2ItemClick(const Sender: TCustomListBox;
  const Item: TListBoxItem);
begin
  ListBox2.BeginUpdate;
  ListBox2.Items:= FileList.Items;
  ListBox2.EndUpdate;
end;