Svish Svish - 13 days ago 7
C# Question

Static readonly vs const

I've read around about

const
and
static readonly
fields. We have some classes which contains only constant values. 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.

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