making a list using inner query in Linq in C#

Question

I am trying to create a sublist using Linq but don\'t understand the error in this. I don\'t think i am doing wrong but i think others eye will help me to sort this issue.

Answer 1

What version of the .NET Framework are you on? The overload of String.Join that takes an IEnumerable was only introduced in v4.0. If you're on an earlier version it's trying to take that IEnumerable and use it as a string[].

Also (this doesn't fix your problem) I think the || in the 4th line should be a &&.