получить (Sender) динамического компонента

var
quantity: integer =4;
pa:TdbImageDataBase;

procedure Form1_OnShow (Sender: TObject; Action: string);
begin
  paCreate;
end;

procedure paCreate;
var
i,j,n:integer = 0;
begin
    for j:=0 to quantity -1 do
    for i:=0 to quantity -1 do
    begin
       pa:=TdbImageDataBase.Create(Form1);
       pa.Parent:=Form1;
       pa.Name:='pa'+IntToStr(n);
       pa.Width:=200;
       pa.Height:=100;
       pa.Top:=5;
       pa.Left:=(200*n)+(5*n);
       pa.Visible:=True;
       pa.OnMouseDown:=@selectpa;
       n:=n+1;
    end;
end;

procedure selectpa (Sender: TObject; MouseLeft, MouseRight, MouseMiddle: boolean; Shift, Alt, Ctrl: boolean; X, Y: Integer);
begin
  showmessage(TdbImageDataBase(Sender).Name);
end;