Func 之间的区别使用委托和 lambda 表达式 [英] Difference between Func<> with delegate and lambda expression

问题描述

在深入了解 C# 的更高级功能时，我遇到了一些代码，但我并不完全了解它们的区别.就是这两行:

while deepening myself to more advanced features of C#, I came across some code, which I didn't exactly know the difference of. It's about these two lines:

Func<string, int> giveLength = (text => text.Length);

和

Func<string, int> giveLength = delegate(string text) { return text.Length; };

这可以用同样的方式:

Console.WriteLine(giveLength("A random string."));

所以基本上..这两行有什么区别?这些行是否编译为相同的 CIL?

So basically.. What is the difference of these two lines? And are these lines compiling to the same CIL?

推荐答案

它们基本上是一样的.它们都是 C# 规范术语中的匿名函数.

They're the same, basically. They're both anonymous functions in C# specification terminology.

Lambda 表达式一般比较简洁，也可以转换成表达式树，这对于进程外 LINQ 至关重要.

Lambda expressions are generally more concise, and can also be converted to expression trees, which are crucial for out-of-process LINQ.

如果您不关心，匿名方法允许您删除参数列表.例如:

Anonymous methods allow you to drop the parameter list if you don't care. For example:

EventHandler handler = delegate { 
    Console.WriteLine("Sender and args don't matter");
};

鉴于后一点很少需要，匿名方法正在成为现代 C# 中的濒危物种.Lambda 表达式更为常见.

Given how rarely the latter point is required, anonymous methods are becoming an endangered species in modern C#. Lambda expressions are much more common.

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