unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    ShapeObject: TShape;
    ShapeList: TComboBox;

    procedure FormCreate(Sender: TObject);
    procedure ShapeListChange(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.FormCreate(Sender: TObject);
begin
    ShapeList.ItemIndex:=0;  
end;

procedure TForm1.ShapeListChange(Sender: TObject);
begin
   Case  ShapeList.ItemIndex of
   //Circle
      0:ShapeObject.Shape:=stCircle;
   //Rectangle
      1:ShapeObject.Shape:=stRectangle;
   //Ellipse
      2:ShapeObject.Shape:=stEllipse;
   //Round Rectangle
      3:ShapeObject.Shape:=stRoundRect;
   //Square
      4:ShapeObject.Shape:=stSquare;
   end;

end;

end.
