关于接口和类的泛型转换 [英] about generic convert of interface and class

问题描述

例如，我声明这样的代码：

公共类A

{}

公共类B：A

{}

公共接口ISubject

{}

公共类ConcreteSubject：ISubject

{}



如果我写这样的代码是错误的：

var collectionWithClass = new List （）;

var baseCollectionWithClass =（List ）collectionWithClass;

如果我写这样的代码是正确的：

var collection = new List< concretesubject>（） ;

var baseCollection =（List< isubject>）集合;

i不明白为什么，我需要帮助，请！

for example, i declare code like this:
public class A
{}
public class B : A
｛｝
public interface ISubject
{}
public class ConcreteSubject : ISubject
{}

It is wrong if i write code like this :
var collectionWithClass = new List();
var baseCollectionWithClass = (List) collectionWithClass;
It is right if i write code like this:
var collection = new List<concretesubject>();
var baseCollection = (List<isubject>) collection;
i did't understand it's why, i need help, please!

推荐答案

我不明白你的问题是什么......

I don't understand what you question is about...

这篇关于关于接口和类的泛型转换的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！