c# - 何时使用属性而不是函数

Question

这可能是个人喜好问题，但是什么时候在代码中使用属性而不是函数

例如获取错误日志我可以说

string GetErrorLog()
{
      return m_ErrorLog;
}

或者我可以

string ErrorLog
{
     get { return m_ErrorLog; }
}

您如何决定使用哪一个？我的用法似乎不一致，我正在寻找一个好的一般经验法则。谢谢。

Answer 1

如果满足以下条件，我倾向于使用属性:

• 该属性将返回一个单一的逻辑值
• 涉及很少或没有逻辑(通常只是返回一个值，或者做一个小的检查/返回值)

如果满足以下条件，我倾向于使用方法:

• 返回值将涉及大量工作 - 即:它将从数据库中获取，或者可能需要“时间”的东西
• 获取或设置值涉及很多逻辑

---

此外，我建议查看 Microsoft's Design Guidelines for Property Usage .他们建议:

Use a property when the member is a logical data member.

Use a method when:

• The operation is a conversion, such as Object.ToString.
• The operation is expensive enough that you want to communicate to the user that they should consider caching the result.
• Obtaining a property value using the get accessor would have an observable side effect.
• Calling the member twice in succession produces different results.
• The order of execution is important. Note that a type's properties should be able to be set and retrieved in any order.
• The member is static but returns a value that can be changed.
• The member returns an array. Properties that return arrays can be very misleading. Usually it is necessary to return a copy of the internal array so that the user cannot change internal state. This, coupled with the fact that a user can easily assume it is an indexed property, leads to inefficient code. In the following code example, each call to the Methods property creates a copy of the array. As a result, 2n+1 copies of the array will be created in the following loop.