摘要： 先看个例子,此代码在c# 4.0下可以编译通过,因为c#4.0才开始支持逆变和协变代码 Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/--usingSystem;usingSystem.Collections.Generic;usingSystem.Li... 阅读全文