C#4.0中的OptionalAttribute和可选参数有什么区别 [英] What is the difference between OptionalAttribute and optional parameters in C# 4.0

问题描述

我正在研究别人的代码，有这样一种方法:

I'm researching someone else's code and there is a method like this:

public SomeClass DoSomething(string param1, [Optional, DefaultParameterValue("")] string optional)

为什么有人会使用这些属性代替

Why would someone use these attributes instead of

public SomeClass DoSomething(string param1, string optional = "")

在行为上有什么不同吗?

Is there any difference in the behavior, etc.?

推荐答案

例如，如果他们没有使用C#4，该怎么办?我相信第二个版本将完全编译成第一个版本...

If they weren't using C# 4, for example? I believe the second version will compile into exactly the first version...

(我都编译了它们，并通过ILDASM运行它们-没有显着差异.)

(I've compiled them both and run them through ILDASM - there were no significant differences.)

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