了解协变和逆变在C＃4.0 [英] Understanding Covariance and Contravariance in C# 4.0

问题描述

我看了一个关于它的视频第9频道，但我真的不明白了。

I watched a video about it on Channel 9 but I didn't really understand it much.

有人可以给我这些，很容易理解一个简单的例子？之后，也许它将如何在实践中使用？

Can someone please give me a simple example about these that's easy to understand? After that maybe how it would be used in practice?

推荐答案

我也想过这个视频由埃里克利珀是非常明确的：

I also thought this video by Eric Lippert was very clear:

1部分：<一href="http://msdn.microsoft.com/en-us/vcsharp/ee672314.aspx">http://msdn.microsoft.com/en-us/vcsharp/ee672314.aspx

2部分：<一href="http://msdn.microsoft.com/en-us/vcsharp/ee672319.aspx">http://msdn.microsoft.com/en-us/vcsharp/ee672319.aspx

这也带来了，我从来没有听说过，不安全的协方差数组一个有趣的案例。

It also brings up an interesting case that I had never heard about before, about unsafe covariance with arrays.

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