Just to add to @Jason True's answer, it is important to realise that just putting 'static' on a method doesn't guarantee that the method will be 'pure'. It will be stateless with regard to the class in which it is declared, but it may well access other 'static' objects which have state (application configuration etc.), this may not always be a bad thing, but one of the reasons that I personally tend to prefer static methods when I can is that if they are pure, you can test and reason about them in isolation, without having to worry about the surrounding state.

它有助于控制名称空间污染。

我相信这不会发生在您的情况下，但是在我不得不忍受维护的一些代码中，我看到了使用大量静态方法的“坏味道”。

不幸的是，它们是假定特定应用程序状态的静态方法。(当然，每个应用程序只有一个用户!为什么不让User类在静态变量中跟踪它呢?)它们是访问全局变量的光荣方法。它们还有静态构造函数(!)，这几乎总是一个坏主意。(我知道有一些合理的例外)。

然而，静态方法在排除域逻辑(实际上不依赖于对象实例的状态)时非常有用。它们可以使您的代码更具可读性。

只要确保你把它们放在正确的地方。静态方法是否侵入式地操纵其他对象的内部状态?能不能证明他们的行为属于其中一类呢?如果你没有正确地分离问题，你以后可能会头疼。

读起来很有趣: http://thecuttingledge.com/?p=57

ReSharper实际上并不是建议您将方法设置为静态的。 你应该问问自己，为什么这个方法在那个类中，而不是在它的签名中出现的类之一…

但ReSharper documentaion是这么说的: http://confluence.jetbrains.net/display/ReSharper/Member+can+be+made+static

Just to add to @Jason True's answer, it is important to realise that just putting 'static' on a method doesn't guarantee that the method will be 'pure'. It will be stateless with regard to the class in which it is declared, but it may well access other 'static' objects which have state (application configuration etc.), this may not always be a bad thing, but one of the reasons that I personally tend to prefer static methods when I can is that if they are pure, you can test and reason about them in isolation, without having to worry about the surrounding state.

在我看来，性能、名称空间污染等都是次要的。问问自己什么是合乎逻辑的。该方法在逻辑上操作类型的实例，还是与类型本身相关?如果是后者，则将其设置为静态方法。只有当它与不受您控制的类型相关时，才将其移动到实用程序类中。

Sometimes there are methods which logically act on an instance but don't happen to use any of the instance's state yet. For instance, if you were building a file system and you'd got the concept of a directory, but you hadn't implemented it yet, you could write a property returning the kind of the file system object, and it would always be just "file" - but it's logically related to the instance, and so should be an instance method. This is also important if you want to make the method virtual - your particular implementation may need no state, but derived classes might. (For instance, asking a collection whether or not it's read-only - you may not have implemented a read-only form of that collection yet, but it's clearly a property of the collection itself, not the type.)