我什么时候应该写静态方法？ [英] When should I write Static Methods?

问题描述

所以，我明白什么是静态方法或字段，我只是想知道何时使用它们。也就是说，编写代码是什么设计本身借给用静态方法和字段时。

So I understand what a static method or field is, I am just wondering when to use them. That is, when writing code what design lends itself to using static methods and fields.

一个常见的​​模式是使用静态方法作为一个静态的工厂，但是这可以很容易地通过重载构造函数来完成。正确？例如：

One common pattern is to use static methods as a static factory, but this could just as easily be done by overloading a constructor. Correct? For example:

var bmp = System.Drawing.Bitmap.LoadFromFile("Image01.jpg");

对于静态字段，正在创造singelton对象他们的最好用？

As for static fields, is creating singelton-objects their best use?

推荐答案

它给人的意图有更好的了解，当你使用一个静态的工厂 - 它也可以让你有采取不同的工厂相同的参数类型，但具有不同的意义。例如，想象一下，如果有位图LoadFromResource（字符串） - 它不可能有两个构造函数，这两个字符串了。

It gives a better idea of the intent when you use a static factory -- it also lets you have different factories that take the same argument types but have a different meaning. For example, imagine if Bitmap had LoadFromResource(string) -- it would not be possible to have two constructors that both took string.

修改 ：从在评论stevemegson

EDIT: From stevemegson in the comments

一个静态的工厂也可以返回空值，并且可以更容易地返回实例，它从缓存中了。我的许多类都有一个静态FromId（INT）从一个主键得到一个例子，如果我们有一个返回一个现有的缓存实例。

A static factory can also return null, and can more easily return an instance that it got from cache. Many of my classes have a static FromId(int) to get an instance from a primary key, returning an existing cached instance if we have one.

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