简单的Dll例子

创建DLL文件 

 Delphi -> New->Other -> Dynamic link libray

library SimpleTestDll;

uses
  SysUtils,
  Classes,Dialogs;
//简单的一个例子
procedure ShowDllMsg;
begin
   ShowMessage('简单的一个例子');
end;

//两个数相加
function Add(Num1,Num2:Integer):Integer;stdcall;
begin
   Result := Num1 + Num2;
end;
{$R *.res}

//提供名称给外部单元使用 然点编译成dll

exports
  ShowDllMsg,Add;
begin
end.

unit Unit2;

interface

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

type
  TForm2 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Edit1: TEdit;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

//external 指明函数的来源
procedure ShowDllMsg; external 'SimpleTestDll.dll';
function Add(Num1,Num2: Integer):Integer;Stdcall;external  'SimpleTestDll.dll';

var
  Form2: TForm2;

implementation

{$R *.dfm}

procedure TForm2.Button1Click(Sender: TObject);
begin
  ShowDllMsg;//显示'简单的一个例子'

end;

procedure TForm2.Button2Click(Sender: TObject);
begin
  Edit1.Text := IntToStr(Add(1,2));//3

end;

end.