Delphi生成即调用带窗体的Dll

library frmDll;

{ Important note about DLL memory management: ShareMem must be the
  first unit in your library's USES clause AND your project's (select
  Project-View Source) USES clause if your DLL exports any procedures or
  functions that pass strings as parameters or function results. This
  applies to all strings passed to and from your DLL--even those that
  are nested in records and classes. ShareMem is the interface unit to
  the BORLNDMM.DLL shared memory manager, which must be deployed along
  with your DLL. To avoid using BORLNDMM.DLL, pass string information
  using PChar or ShortString parameters. }

uses
  SysUtils,
  Classes,
  Forms,
  FormDll in 'FormDll.pas' {Form1};

{$R *.res}

function GetDllForm:TForm;stdcall;export;//定义导出方法；
begin
  result:=Form1; //函数返回类型为一个窗体；
end;
exports
  GetDllForm;//声明可导出的方法；

begin
end.

unit FormDll;

interface

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

type
  TForm1 = class(TForm)
    btn1: TButton;
    procedure btn1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.btn1Click(Sender: TObject);
begin
  MessageDlg('你已经成功调用了Dll控件',mtinformation,[mbOK],);
end;

initialization //在单元中放在文件结尾前，包含用来初始化单元的代码，它在主程序运行前运行并且只运行一次
begin
  Form1:=TForm1.Create(Application);
end;

finalization//在单元中放在 initialization 和 end. 之间，包含了单元退出时的代码。程序退出时运行并且只运行一次。
begin
  Form1.Free;
end;

end.

unit testdll;

interface

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

type
  TForm1 = class(TForm)
    btn1: TButton;
    procedure btn1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  //function GetDllForm:TForm;

implementation

{$R *.dfm}
function GetDllForm:TForm;external 'frmDll.dll';  //声明从函数frmDll.dll中调用函数

procedure TForm1.btn1Click(Sender: TObject);
var
  AForm:TForm;
begin
  AForm:=GetDllForm;
  AForm.Show;
end;

end.