DLL文件中Form的使用

贴出此文之前，未查阅过任何相似文章，如有相同，敬请见谅，并告示(注:本人曾就同一DLL中一窗体调用附窗体，如何实现之问题，请教过一前辈，但前辈笑笑未言)，此为我在写动态元件时想到的一方法，结果通过,各位见谅。我为初学，而求学路见艰难，贴出只望对象我一样初学者给点帮助，无他。
library DLLPJ;

uses
  SysUtils,
  Classes,
  Unit1 in 'Unit1.pas' {Form1},
  Unit2 in 'Unit2.pas' {Form2};

{$R *.res}

exports
  ShowMainPRGWin;
 
begin
end.
----------
unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Unit2,Dialogs, StdCtrls;
  //1.附窗体单元加在此处
type
  TForm1 = class(TForm)
　  Button1: TButton;
　  procedure Button1Click(Sender: TObject);
  private
　  { Private declarations }
  public
　  { Public declarations }
  end;

var
  Form1: TForm1;
  Form2: TForm2; //2.附窗体定义在此处
// Declare the export function of windows of the main DLL
function ShowMainPRGWin(AHandle:THandle):BOOL;StdCall;

implementation

{$R *.dfm}
function ShowMainPRGWin(AHandle:THandle):BOOL;
begin
  Form1:=TForm1.Create(application);
  Form2:=TForm2.Create(Application); //3.创建附窗体
  try
　  Form1.ShowModal;
　  Result:=False;
  Finally
　  Form1.Free;
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  Form2.ShowModal;//4.在主窗体上调用附窗体
end;

end.
------------
unit Unit2;

interface

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

type
  TForm2 = class(TForm)
  private
　  { Private declarations }
  public
　  { Public declarations }
  end;

var
  Form2: TForm2;

implementation

{$R *.dfm}

end.
----------
//在其他窗体上调用DLL的定义及方法
procedure ShowMainPRGWin(AHandle:THandle);StdCall External 'DLLPJ.DLL';

ShowMainPRGWin(1);