Recommended .NET Class for a collection of unique integers?

.net, c#

Solution

HashSet:

The `HashSet<T>` class provides high-performance set operations. A set is a collection that contains no duplicate elements, and whose elements are in no particular order...

The capacity of a `HashSet<T>` object is the number of elements that the object can hold. A `HashSet<T>` object's capacity automatically increases as elements are added to the object.

The `HashSet<T>` class is based on the model of mathematical sets and provides high-performance set operations similar to accessing the keys of the `Dictionary<TKey, TValue>` or `Hashtable` collections. In simple terms, the `HashSet<T>` class can be thought of as a `Dictionary<TKey, TValue>` collection without values.

A `HashSet<T>` collection is not sorted and cannot contain duplicate elements...

Problem

What would you recommend for class that needs to keep a list of unique integers? I'm going to want to Add() integers to the collection and also check for existence e.g. Contains(). Would be nice to also get them in a list as a string for display, ie. "1, 5, 10, 21".

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