dll

library MyDll;

{ 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,
  UAbout in 'UAbout.pas' {frmAbout};

{$R *.res}
function MyAdd(x,y:integer):integer;stdcall;
begin
    result:=x+y;
end;
procedure ShowAbout(PName,Author,Version,Contact:string);stdcall;
begin
    frmAbout:=TfrmAbout.Create(Application);
    with frmAbout do
    begin
        Label1.Caption:=PName;
        Label2.Caption:='作者：'+Author;
        Label3.Caption:='版本号：'+Version;
        Label5.Caption:=Contact;
    end;
    frmAbout.ShowModal;
    frmAbout.Free;

end;

exports
  MyAdd, ShowAbout;
begin
 // ShowMessage('Hi,dll!');
end.
 

unit UAbout;

interface

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

type
  TfrmAbout = class(TForm)
    Image1: TImage;
    Label1: TLabel;
    Label2: TLabel;
    Label3: TLabel;
    Label4: TLabel;
    Label5: TLabel;
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  frmAbout: TfrmAbout;

implementation

{$R *.dfm}

end.

unit UdllClient;

interface

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

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);

  private
    { Private declarations }
  public
    { Public declarations }

  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

function MyAdd(x,y:integer):integer;stdcall;external 'MyDll.dll';
procedure ShowAbout(PName,Author,Version,Contact:string);stdcall;external 'MyDll.dll';
procedure TForm1.Button1Click(Sender: TObject);
begin
  ShowMessage('3+5='+IntToStr(MyAdd(3,5)));
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
ShowAbout('TestDll','----','1.0.0','QQ:-------')
end;

end.

unit UDyClient;

interface

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

type
  TForm1 = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
type
  TMyProc=procedure;stdcall;
var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
var
  HInst:THandle;//存储加载的dll文件句柄
  FPointer:TFarProc;//dll文件中指定函数地址
  MyFunc:TMyProc;//TMyProc过程的变量
begin
  HInst:=LoadLibrary('MyDll.dll');//加载dll
  if HInst>0 then//如果加载成功
     try
        FPointer:=GetProcAddress(HInst,'ShowAbout');//获取函数地址
        if FPointer<>nil then
        begin
          MyFunc:=TMyProc(FPointer);
          MyFunc('TestDll','----','1.0.0','QQ:-----');  //
        end
        else//获取函数地址失败
            ShowMessage('ShowAbout未找到！');
        finally
          FreeLibrary(HInst);
        end
     else
        ShowMessage('加载MyDll.dll失败');
end;

end.