unitUnit1;
interface

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

type
TForm1 = class(TForm)
Button1: TButton;
RadioGroup1: TRadioGroup;
procedure RadioGroup1Click(Sender: TObject);
procedure FormCreate(Sender: TObject);
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

var
R: TRect;

procedure TForm1.FormCreate(Sender: TObject);
begin
RadioGroup1.Items.CommaText := 'Undo,Rect,Bounds';
R := Button1.BoundsRect;
end;

procedure TForm1.RadioGroup1Click(Sender: TObject);
begin
case RadioGroup1.ItemIndex of
0: Button1.BoundsRect := R;
1: Button1.BoundsRect := Rect(50,50,100,80); {参数3、4 是一个点}
2: Button1.BoundsRect := Bounds(50,50,100,80);{参数3、4 分别是宽度与高度}
end;
end;

end.