Dictionary.ElementAt method is visible in some classes, but not others

Question

I have a Dictionary whose elements I need to iterate through and make changes. I cannot use foreach statement, since it sometimes throws InvalidOperationException, saying that t

Answer 1

ElementAt is an extension method defined in System.Linq.Enumerable.

You need to add a using clause to make it visible:

using System.Linq;

Note that ElementAt on a Dictionary doesn't make a lot of sense, though, as the dictionary implementation does not guarantee elements to be in any specific order, nor that the order does not change if you make changes to the dictionary.