delphi中的窗体怎么取得焦点

例如：有form1、form2 两个窗体，form1中有两个按钮，
button2是显示form2并将焦点设置于edit3。  程序如下：

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

uses Unit2;

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
    form1.SetFocus;
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
    form2.Show;
    //form2.setfocus;
    form2.Edit3.SetFocus;
end;

end.

窗体名.active:=true;