HashSet conversion to List

Question

I have looked this up on the net but I am asking this to make sure I haven't missed out on something. Is there a built-in function to convert HashSets to Lists in C#? I need to avoid duplicity of elements but I need to return a List.

Answer 1

Here's how I would do it:

   using System.Linq;    HashSet<int> hset = new HashSet<int>();    hset.Add(10);    List<int> hList= hset.ToList(); 

HashSet is, by definition, containing no duplicates. So there is no need for Distinct.

Answer 2

Two equivalent options:

HashSet<string> stringSet = new HashSet<string> { "a", "b", "c" }; // LINQ's ToList extension method List<string> stringList1 = stringSet.ToList(); // Or just a constructor List<string> stringList2 = new List<string>(stringSet); 

Personally I'd prefer calling ToList is it means you don't need to restate the type of the list.

Contrary to my previous thoughts, both ways allow covariance to be easily expressed in C# 4:

    HashSet<Banana> bananas = new HashSet<Banana>();             List<Fruit> fruit1 = bananas.ToList<Fruit>();     List<Fruit> fruit2 = new List<Fruit>(bananas);