Delphi DLL 字符串传递例子

【核心代码】

unit UnitMain;

interface

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

type
  TMyObj = class
    id: Integer;
    Name: string;
    address: Pchar;
  end;

  TForm1 = class(TForm)
    btn1: TButton;
    Memo1: TMemo;
    btn2: TButton;
    Button1: TButton;
    procedure btn1Click(Sender: TObject);
    procedure btn2Click(Sender: TObject);
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

{$Warnings OFF}

procedure Teststr(p: PChar); external 'test.dll';
procedure TestObj(p: TMyObj); external 'test.dll';

procedure TForm1.Btn1Click(Sender: TObject);
var
  p: PChar;
  str: string;
  i: Integer;
begin
  for i := 1 to 8000 do
  begin
    randomize();
    str := '我来自Exe 程序'   IntToStr(Random(100))   #$D#$A;
    p := StrAlloc(8192);
    StrCopy(p, PChar(str));

    Teststr(p); // 调用 Dll 函数

    memo1.Text := p   ', 我们两个做游戏.';
    StrDispose(p);
    Application.ProcessMessages;
  end;
end;

procedure TForm1.btn2Click(Sender: TObject);
var
  p: TMyObj;
  str: string;
begin
  p := TMyObj.Create;
  p.id := 0;
  p.Name := '我来自Exe 程序'   IntToStr(Random(100))   #$D#$A;
  TestObj(p); // 调用 Dll 函数

  memo1.Text := IntTostr(p.id)    ', '   p.Name;
  FreeAndNil(p);
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  p: TMyObj;
  str: string;
  i: integer;
begin
  for i := 1 to 8000 do
  begin
    p := TMyObj.Create;
    p.address := StrAlloc(8192);
    strcopy(p.address, 'yyuyuyuyu');
    p.id := 0;
    p.Name := '我来自Exe 程序'   IntToStr(Random(100))   #$D#$A;
    TestObj(p); // 调用 Dll 函数

    memo1.Text := IntTostr(p.id)    ', '   p.address;
    FreeAndNil(p);
    Application.ProcessMessages;
  end;
end;

{$Warnings ON}
end.