Question

From this Answer, I came to know that KeyValuePair are immutables.

I browsed through the docs, but could not find any information regarding immutable behavior.

I was wondering how to determine if a type is immutable or not?

Answer 1

I don’t think there’s a standard way to do this, since there is no official concept of immutability in C#. The only way I can think of is looking at certain things, indicating a higher probability:

1) All properties of the type have a private set

2) All fields are const/readonly or private

3) There are no methods with obvious/known side effects

4) Also, being a struct generally is a good indication (if it is BCL type or by someone with guidelines for this)

Something like an ImmutabeAttribute would be nice. There are some thoughts here (somewhere down in the comments), but I haven’t seen one in “real life” yet.