| How to use SortedDictionary, SortedList, and SortedSet in C# Take advantage of the SortedDictionary, SortedList, and SortedSet classes in C# to store key-value pairs and sort them based on keys. Thinkstock SortedDictionary, SortedList, and SortedSet are collection classes that store key-value pairs and can be sorted based on the keys. A SortedSet is a collection that is maintained in sorted order. A SortedList is a collection that lets you retrieve the keys and/or values using indexes. A SortedDictionary lacks indexes but offers faster insertion and removal of unsorted data than a SortedList. This article talks about SortedDictionary, SortedList, and SortedSet, how they differ, and how we can work with them in C#. To work with the code examples provided in this article, you should have Visual Studio 2019 installed in your system. If you don’t already have a copy, you can download Visual Studio 2019 here.