program Demo1;{  Create Date: 2014-06-29  Author: P.S.M  1.接口Demo1}{$APPTYPE CONSOLE}uses  SysUtils;{定义接口}type ITestInterface = interface   {GUID通过CTRL+G自动产生}   [‘{15EAD871-2B5E-4F51-A14E-7D518A2371EF}‘]   procedure Test; end;{TInterfacedObject 实现了_AddRef, _Release方法可以自动释放对象} TTest1 = class(TInterfacedObject, ITestInterface) public   {接口实现}   procedure  ITestInterface.Test = GetTest;   {测试接口}   procedure GetTest;   {重载Destroy方法}   destructor Destroy;override; end; TTest2 = class(TInterfacedObject, ITestInterface) public   {接口实现}   procedure Test;   {重载Destroy方法}   destructor Destroy;override; end;{ TTest }destructor TTest1.Destroy;begin  WriteLn(‘对象1释放了‘);  sleep(2000);  inherited Destroy;end;procedure TTest1.GetTest;begin    WriteLn(‘接口1‘);end;{ TTest2 }destructor TTest2.Destroy;begin  WriteLn(‘对象2释放了‘);  sleep(2000);  inherited Destroy;end;procedure TTest2.Test;begin  WriteLn(‘接口2‘);end;procedure Output(Obj: ITestInterface);begin    Obj.Test;end;var ITest1, ITest2: ITestInterface;begin   {接口什么时候释放？ 当它的引用计数为0是自动释放，作用域有效在函数体bend end，函数退出时自动减少引用计数 }  try    ITest1 := TTest1.Create;    ITest2 := TTest2.Create;    Output(Itest1);    OutPut(ITest2);  except    on E: Exception do      Writeln(E.ClassName, ‘: ‘, E.Message);  end;end.