unit Unit1;

 interface

 uses

   Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,

   Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.ComCtrls, Vcl.StdCtrls,

   Unit2;

 type

   TForm1 = class(TForm)

     Button1: TButton;

     Button2: TButton;

     Button3: TButton;

     PageControl1: TPageControl;

     TabSheet1: TTabSheet;

     procedure Button1Click(Sender: TObject);

   private

     { Private declarations }

   public

     { Public declarations }

   end;

 var

   Form1: TForm1;

   Form2: TForm2;

 implementation

 {$R *.dfm}

 procedure TForm1.Button1Click(Sender: TObject);

 begin

   if not Assigned(Form2) then

     Form2 := TForm2.Create(nil);

   try

     Form2.ManualDock(PageControl1.Pages[]);  // 嵌入PageControl1.Pages[0]

     Form2.Show;

   except

     Form2.Close;

     Exception.Create('Error');

   end;

 end;

 end.