深入类中的方法[2] - 关于覆盖与重定义

//标准的覆盖是这样的

TBass =class  

procedure Proc; virtual; {或用 dynamic}

end; 

TChild = class(TBass)

  procedure Proc; override;

end;

---

//以下几种情况属于重定义, 其中例 3-5 还会有编译提示(不提倡如下方法)

{例1}

TBass = class

  procedure Proc;

end; 

TChild = class(TBass)

  procedure Proc;

end; 

{例2}

TBass = class

  procedure Proc;

end; 

TChild = class(TBass)

  procedure Proc; virtual;

end; 

{例3}

TBass = class

  procedure Proc; virtual;

end; 

TChild = class(TBass)

  procedure Proc; virtual;

end; 

{例4}

TBass = class

  procedure Proc; virtual;

end; 

TChild = class(TBass)

  procedure Proc;

end; 

{例5}

TBass = class

  procedure Proc; virtual;

end; 

TChild = class(TBass)

  procedure Proc; dynamic;

end; 

{上面这五种情况我们尽量不要使用}

---

 //方法重定义时, 避免编译提示的办法

{办法1: 使用 reintroduce 指示字}

TBass = class

  procedure Proc; virtual;

end; 

TChild = class(TBass)

  procedure Proc; reintroduce;

end; 

{办法2: 使用编译器指令}

TBass = class

  procedure Proc; virtual;

end; 

{$WARNINGS OFF}

TChild = class(TBass)

  procedure Proc; virtual;

end;

{$WARNINGS ON}