我对泛型的理解以及它们如何使用和不可以使用有些困难。
我有一个像这样的通用类 TControlMediator:
TControlMediator<C, T> = class
private
FMediatedComponent: C;
public
constructor Create(ComponentToMediate: C);
function GetValue: T; virtual; abstract;
procedure SetValue(Value: T); virtual; abstract;
property MediatedControl: C read FMediatedComponent;
end;
然后,我为我想要调解的每个控件类型创建“具体”子类:
TEditMediator = class(TControlMediator<TEdit, string>)
public
function GetValue: string; override;
procedure SetValue(Value: string); override;
end;
到目前为止,一切似乎都正常。但是,当我想要 TControlMediator 后代的列表,或者将 TControlMediator 作为方法的参数时,就会出现问题:
TViewMediator = class
private
FControlMediators: TList<TControlMEdiator<C, T>>;
public
procedure registerMediator(AControlMediator: TControlMediator<C, T>);
procedure unregisterMediator(AControlMediator: TControlMediator<C, T>);
end;
编译器因致命错误而停止:
[DCC Error] mediator.pas(23): E2003 Undeclared identifier: 'C'
[DCC Error] mediator.pas(28): E2007 Constant or type identifier expected
有人知道这应该如何完成吗?