Question

How do I convert an array to a hash set ?

string[]  BlockedList = BlockList.Split(new char[] { ';' },     
StringSplitOptions.RemoveEmptyEntries);

I need to convert this list to a hashset.

Answer 1

You do not specify what type BlockedList is, so I will assume it is something that derives from IList (if meant to say String where you wrote BlockList then it would be a string array which derives from IList).

HashSet has a constructor that takes an IEnumerable, so you need merely pass the list into this constructor, as IList derives from IEnumerable.

var set = new HashSet(BlockedList);