I've read around about const and static readonly fields. We have some classes which contain only constant values. They are used for various things around in our system. So I am wondering if my observation is correct:
Should these kind of constant values always be static readonly for everything that is public? And only use const for internal/protected/private values?
What do you recommend? Should I maybe even not use static readonly fields, but rather use properties maybe?
Answer
public static readonly fields are a little unusual; public static properties (with only a get) would be more common (perhaps backed by a private static readonly field).
const values are burned directly into the call-site; this is double edged:
- it is useless if the value is fetched at runtime, perhaps from config
- if you change the value of a const, you need to rebuild all the clients
- but it can be faster, as it avoids a method call...
- ...which might sometimes have been inlined by the JIT anyway
If the value will never change, then const is fine - Zero etc make reasonable consts ;p Other than that, static properties are more common.