Question

我有一个基类和10个派生自该类的类。基类包含除procedure of object类型的参数之外的函数。像这样

 mytype = procedure (a : integer) of object;

 baseclass = class
 public
   procedure myproc(cont handler : mytype ) ;
 end; 
 procedure baseclass.myproc(cont handler : mytype ) ;
 begin
 // do something
 end;

我在派生类中重载此函数，即派生类包含相同的函数但具有不同的参数（对象的过程（const handler：integer））。像这样

 base1mytype = procedure (a : string) of object; 

 derivedclass1 = class(baseclass)
 public
   procedure myproc(cont handler : base1mytype ) ;overload;
 end;

 base2mytype = procedure (a : boolean) of object; 
 derivedclass1 = class(baseclass)
 public
   procedure myproc(cont handler : base2mytype ) ;overload;
 end;

依旧.........

我想要一个实现此功能的泛型类，并从该函数派生我的类，例如

   mytype = procedure (a : integer) of object;
    baseclass<T> = class
    public
      procedure myproc(cont handler : T) ;
    end; 
   procedure baseclass<T>.myproc(cont handler : T ) ;
   begin
   // do something
   end;
  and derive classes are like this

deriveclass1  = class<baseclass <string>>
  public
    procedure myproc(cont handler : T) ;
  end;

由于泛型约束不支持类型procedure of object

的约束

Answer 1

您需要一个具有内部类型定义的泛型类：

type
  TBaseClass<T> = class
  public
    type
      THandler = procedure(Arg: T) of object;
  public
    procedure CallHandler(Handler: THandler; Arg: T);
  end;

procedure TBaseClass<T>.CallHandler(Handler: THandler; Arg: T);
begin
  Handler(Arg);
end;

如何做通用就像在delphi中实现类函数一样

1 个答案: