Question

How to Convert IList to IList where SomeObject implements ISomeInterface using covariance in C# 4.0

I have something similar to following

IList<Items> GetItems;

IList<IItems> items = GetItems() as IList<IItems>; 

but items is null;

the answer here was for pre 4.0:

Converting an array of type T to an array of type I where T implements I in C#

Answer 1

why not simply use

IList<Items> GetItems;
IList<IItems> items = GetItems().Cast<IItems>().ToList();