unit Unit1;

interface

uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, StdCtrls;

type

 

//晚绑定，也就是动态调用外部函数主要用以下三个命令：

 

//LoadLibrary：获取 DLL

 

//GetProcAddress：获取函数

 

//FreeLibrary：释放

 

//定义一个过程类型，参数要和需要的函数一致

  TMB =

function(hWnd: HWND; lpText, lpCaption: PChar; uType: UINT): Integer;

stdcall;

  TForm1 =

class(TForm)

    Button1: TButton;

   

procedure Button1Click(Sender: TObject);

   

procedure FormCreate(Sender: TObject);

   

procedure FormDestroy(Sender: TObject);

 

private

    MB: TMB; 

{声明函数 MB}

    inst: LongWord; 

{声明一个变量来记录要使用的 DLL 句柄}

 

public

   

{ Public declarations }

 

end;

var

  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);

begin

  inst := LoadLibrary(

'user32.dll');

 

if inst <>

0

then

    MB := GetProcAddress(inst,

'MessageBoxW');

//    MB := GetProcAddress(inst, 'MessageBoxA'); {Delphi 2009 之前的版本用这句}

end;

//调用测试：

procedure TForm1.Button1Click(Sender: TObject);

var

  t,b: PChar;

begin

  t :=

'标题';

  b :=

'内容';

  MB(

0, b, t,

0);

end;

procedure TForm1.FormDestroy(Sender: TObject);

begin

  FreeLibrary(inst); 

{记得释放}

end;

end.