代码文件:
unit Unit1;interfaceuses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls;type TForm1 = class(TForm) Button1: TButton; Button2: TButton; Button3: TButton; Button4: TButton; procedure Button1Click(Sender: TObject); procedure Button2Click(Sender: TObject); procedure Button3Click(Sender: TObject); procedure Button4Click(Sender: TObject); end; IMyInterface1 = interface function Func1: Integer; function Func2: Integer; end; IMyInterface2 = interface procedure Proc1; procedure Proc2; end; TMyClass1 = class(TInterfacedObject, IMyInterface1, IMyInterface2) public procedure Proc1; procedure Proc2; function Func1: Integer; function Func2: Integer; end;var Form1: TForm1;implementation{$R *.dfm}{ TMyClass1 }function TMyClass1.Func1: Integer;begin ShowMessage('IMyInterface1.Func1'); Result := 0;end;function TMyClass1.Func2: Integer;begin ShowMessage('IMyInterface1.Func2'); Result := 0;end;procedure TMyClass1.Proc1;begin ShowMessage('IMyInterface2.Proc1');end;procedure TMyClass1.Proc2;begin ShowMessage('IMyInterface2.Proc2');end;procedure TForm1.Button1Click(Sender: TObject);var c: TMyClass1;begin c := TMyClass1.Create; c.Func1; c.Func2; c.Proc1; c.Proc2; c.Free;end;procedure TForm1.Button2Click(Sender: TObject);var i1: IMyInterface1;begin i1 := TMyClass1.Create; i1.Func1; i1.Func2;end;procedure TForm1.Button3Click(Sender: TObject);var i2: IMyInterface2;begin i2 := TMyClass1.Create; i2.Proc1; i2.Proc2;end;procedure TForm1.Button4Click(Sender: TObject);var c: TMyClass1; i1: IMyInterface1; i2: IMyInterface2;begin c := TMyClass1.Create; i1 := c; i1.Func1; i1.Func2; i2 := c; i2.Proc1; i2.Proc2;// c.Free; {}end;end. 示例注释(现在应该知道的): { 1、接口命名约定 I 起头, 就像类从 T 打头一样. 2、接口都是从 IInterface 继承而来; 若是从根接口继承, 可省略. 3、接口成员只能是方法、属性, 没有字段. 4、接口成员都是公开的, 不需要 private、protected、public、published 等任何访问限制. 5、因为接口只声明、无实现, 也用不到继承与覆盖相关的修饰(virtual、dynamic、abstract、override). 6、一个接口可以从另一个接口继承, 但不能从多个接口继承; 不过 Delphi.Net 已支持接口的多继承了. 7、一个类可以实现多个接口: TMyClass = class(父类, 接口1, 接口2, ...) end; 8、不过实现接口的类有多么丰富, 接口只拥有自己声明的成员. 9、实现接口的类一般继承于 TInterfacedObject, 直接从 TObject 继承会增加一些麻烦而重复的工作. 10、接口在用完后会自释放, 并同时释放拥有它的类; 这很方便, 但同时带来很多问题.}