delphi 학습노트 2 - 외부 DLL에서 함수 호출(2. 늦게 귀속)

delphi 학습노트 2 - 외부 DLL에서 함수 호출(2. 늦게 귀속)

unit Unit1;

interface

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

type
  //   ，                    ：
  //LoadLibrary：   DLL
  //GetProcAddress：    
  //FreeLibrary：  

  //        ，           
  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;  {     MB}
    inst: LongWord;  {              DLL   }
  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');
end;

//    ：
procedure TForm1.Button1Click(Sender: TObject);
var
  t,b: PChar;
begin
  t := '  ';
  b := '  ';
  MB(0, b, t, 0);
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  FreeLibrary(inst);  {    }
end;

end.