Static methods 静态方法

Delphi联机帮助原文：

Methods are by default static. When a static method is called, the declared (compile-time) type of the class or object variable used in the method call determines which implementation to activate.如果一个方法没有特别声明，那么默认为静态方法。当调用静态方法时，根据方法中类或者对象变量的编译期声明类型来决定调用哪个方法。

例如下例中，Classify就是静态方法。

 

{ TCoder }constructor TCoder.Create;begin  FClassName := 'TCoder';end;function TCoder.Classify: string;begin  Result := ClassName;end;{ TDelphiCoder }constructor TDelphiCoder.Create;begin  FClassName := 'TDelphiCoder';end;function TDelphiCoder.Classify: string;begin  Result := ClassName;end;procedure TForm1.FormCreate(Sender: TObject);var  Coder: TCoder;  DelphiCoder: TDelphiCoder;begin  Coder := TCoder.Create;  ShowMessage(Coder.Classify); //Coder声明为TCoder类型，调用TCoder.Classify，显示TCoder  Coder.Destroy;  Coder := TDelphiCoder.Create;  ShowMessage(Coder.Classify); //Coder声明为TCoder类型，调用TCoder.Classify，由于TDelphiCoder.Create未对TCoder的ClassName属性赋值，故显示为空  ShowMessage(TDelphiCoder(Coder).Classify); //编译时将Coder转换为TDelphiCoder类型，调用TDelphiCoder.Classify，显示TDelphiCoder  Coder.Destroy;  DelphiCoder := TDelphiCoder.Create;  ShowMessage(DelphiCoder.Classify); //DelphiCoder声明为TDelphiCoder类型，调用TDelphiCoder.Classify，显示TDelphiCoder  DelphiCoder.Destroy;end;