[英]Inheriting a generic in c#
I've inherited a large codebase and I'm trying to implement some new functionality into the framework. 我继承了一个大型代码库,我正在尝试在框架中实现一些新功能。 Basically, in order to do it the "right" way, I would have to modify the entire structure of the framework.
基本上,为了以“正确”的方式做到这一点,我将不得不修改框架的整个结构。 since I'm not the guy who designed the framework, nor am I a mind reader, doing so probably isn't going to happen (although I would really love to redesign it all from scratch myself).
因为我不是那个设计框架的人,也不是一个心灵读者,这样做可能不会发生(尽管我真的很想从头开始重新设计它)。
So in order to do what I want, I'm trying to implement a decorator pattern, of sorts. 所以为了做我想做的事,我正在尝试实现一种装饰模式。 This answer from maliger suggests that what I'm doing below is perfectly valid.
马利格的回答表明,我在下面所做的事情是完全有效的。 However, mono doesn't seem to like it;
然而,单声道似乎不喜欢它; it complains that
T
cannot be derived from when I declare HappyDecorator
它抱怨说,
T
无法导出,当我宣布HappyDecorator
Please forgive the overly simplistic example, but it gets the point across. 请原谅过于简单化的例子,但它得到了重点。
public class HappyObject
{
public virtual void print()
{
Console.WriteLine ("I'm happy");
}
}
public class VeryHappyObject : HappyObject
{
public override void print()
{
Console.WriteLine ("I'm very happy");
}
public void LeapForJoy()
{
Console.WriteLine("Leaping For Joy!");
}
}
public class SuperHappyObject : VeryHappyObject
{
public override void print()
{
Console.WriteLine ("I'm super happy!");
}
public void DieOfLaughter()
{
Console.WriteLine("Me Dead!");
}
}
public class HappyDecorator<T> : T where T : HappyObject
{
public string SpecialFactor { get; set; }
public void printMe()
{
Console.WriteLine (SpecialFactor);
print();
}
}
class MainClass
{
public static void Main (string[] args)
{
HappyDecorator<HappyObject> obj = new HappyDecorator<HappyObject> ();
obj.SpecialFactor = Console.ReadLine();
obj.printMe();
}
}
You're typing HappyDecorator to T, but there's no instance of T to use inside that class. 你正在输入HappyDecorator到T,但在该类中没有T的实例。
public class HappyDecorator<T> where T : HappyObject
{
private readonly T _instance;
public HappyDecorator(T instance)
{
_instance = instance;
}
public string SpecialFactor { get; set; }
public void printMe()
{
Console.WriteLine(SpecialFactor);
_instance.print();
}
}
Another alternative is to structure it like this with a generic method instead of a generic class. 另一种方法是使用泛型方法而不是泛型类来构造它。 It's not really a decorator then though:
然而,它并不是真正的装饰者:
public class HappyDecorator
{
public string SpecialFactor { get; set; }
public void printMe<T>(T instance) where T : HappyObject
{
Console.WriteLine(SpecialFactor);
instance.print();
}
}
And call like: 并称之为:
HappyDecorator obj = new HappyDecorator();
obj.SpecialFactor = Console.ReadLine();
obj.printMe(new HappyObject());
I think this is what you are trying to do: 我想这就是你要做的事情:
public interface IhappyObject
{
void Print();
}
public class HappyObject : IhappyObject
{
private IhappyObject obj;
public HappyObject(IhappyObject obj)
{
this.obj = obj;
}
public void Print()
{
obj.Print();
}
}
public class VeryHappyObject : IhappyObject
{
public void Print()
{
Console.WriteLine("I'm very happy");
}
}
public class SuperHappyObject : IhappyObject
{
public void Print()
{
Console.WriteLine("I'm super happy!");
}
}
static void Main(string[] args)
{
HappyObject obj = new HappyObject(new SuperHappyObject());
obj.Print();
}
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