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Reading this article by Microsoft I came across these three terms, with the following meanings (translation via Google Translate):
- Covariance
Allows to use a type more derived than originally specified.
You can assign an instance of IEnumerable<Derived> to a variable of the type IEnumerable<Base>.
- Contravariance
Allows you to use a more generic type (less derivative) than originally specified.
You can assign an instance of IEnumerable<Base> to a variable of the type IEnumerable<Derived>.
- Invariance
It means that you can only use the originally specified type; so a generic invariant type parameter is neither covariant nor contravariant.
Unable to assign an instance of IEnumerable<Base> to a type variable IEnumerable<Derived> or vice versa.
I would like to know, in other words, what those words mean?
That? http://answall.com/q/32880/101 Practical example: http://answall.com/q/75097/101
– Maniero
@bigown I searched and did not find. I will vote to close here, thank you very much :p
– Randrade