main.pas

来自「《Delphi开发人员指南》配书原码」· PAS 代码 · 共 70 行

unit Main;
{$C FIXED DEMANDLOAD PERMANENT}

interface

uses
  SysUtils, WinTypes, WinProcs, Messages, Classes, Graphics, Controls,
  Forms, Dialogs, StdCtrls;

type
  TMainForm = class(TForm)
    CallBtn: TButton;
    Edit1: TEdit;
    Label1: TLabel;
    procedure CallBtnClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  MainForm: TMainForm;

implementation

{$R *.DFM}

uses WOW16;

const
  ExeStr = 'The 32-bit DLL has called back into the 16-bit EXE. ' +
           'The string to the EXE is: "%s"';

function CallBackFunc(P: PChar): Longint; export;
begin
  ShowMessage(Format(ExeStr, [StrPas(P)]));
  Result := StrLen(P);
end;

procedure TMainForm.CallBtnClick(Sender: TObject);
var
  H: THandle32;
  R, P: Longint;
  AStr: PChar;
begin
  { load 32-bit DLL }
  H := LoadLibraryEx32W('TestDLL.dll', 0, 0);
  AStr := StrNew('I love DDG.');
  try
    if H > 0 then
    begin
      { Retrieve address of proc from 32-bit DLL }
      TFarProc(P) := GetProcAddress32W(H, 'DLLFunc32');
      if P > 0 then
      begin
        { Call proc in 32-bit DLL }
        R := Call32BitProc(P, [Longint(AStr), Longint(@CallBackFunc)],
          1);
        Edit1.Text := IntToStr(R);
      end;
    end;
  finally
    StrDispose(AStr);
    if H > 0 then FreeLibrary32W(H);
  end;
end;

end.