What is the difference between const and readonly in C#?

Question

What is the difference between const and readonly in C#?

When would you use one over the other?

Answer 1

• when to use const or readonly

  • const

    • compile-time constant: absolute constant, value is set during declaration, is in the IL code itself

  • readonly

    • run-time constant: can be set in the constructor/init via config file i.e. App.config, but once it initializes it can't be changed