Cannot convert from List to List

Question

I\'m trying to pass A list of DerivedClass to a function that takes a list of BaseClass, but I get the error:

cannot convert from 
         


        

Answer 1

When you have a class derived from a base class, any containers of those classes are not automatically derived. So you cannot just cast a List to a List.

Use .Cast() to create a new list where each object is cast back to the base class:

List list1 = new List();
List list2 = list1.Cast().ToList();

Note that this is a new list, not a cast version of your original list, so operations on this new list will not reflect on the original list. Operations on the contained objects will reflect, however.