How to create an OrderedDictionary in C# Last Updated : 11 Jul, 2025 Comments Improve Suggest changes Like Article Like Report OrderedDictionary() constructor is used to initialize a new instance of the OrderedDictionary class which will be empty and will have the default initial capacity. OrderedDictionary Class represents a collection of key/value pairs that are accessible by the key or index. It is present in System.Collections.Specialized namespace. Syntax: public OrderedDictionary(); Example 1: csharp // C# Program to illustrate how // to create a OrderedDictionary using System; using System.Collections; using System.Collections.Specialized; class Geeks { // Main Method public static void Main(String[] args) { // od is the OrderedDictionary object // OrderedDictionary() is the constructor // used to initializes a new // instance of the OrderedDictionary class OrderedDictionary od = new OrderedDictionary(); // Count property is used to get the // number of elements in OrderedDictionary // It will give 0 as no elements // are present currently Console.WriteLine("The number of elements: " +od.Count); } } Output: The number of elements: 0 Example 2: csharp // C# Program to illustrate how // to create a OrderedDictionary using System; using System.Collections; using System.Collections.Specialized; class Geeks { // Main Method public static void Main(String[] args) { // od is the OrderedDictionary object // OrderedDictionary() is the constructor // used to initializes a new // instance of the OrderedDictionary class OrderedDictionary od = new OrderedDictionary(); Console.Write("Before Add Method: "); // Count property is used to get the // number of elements in OrderedDictionary // It will give 0 as no elements // are present currently Console.WriteLine(od.Count); // Adding key/value pairs in od od.Add("1", "C"); od.Add("2", "C++"); od.Add("3", "Java"); od.Add("4", "C#"); Console.Write("After Add Method: "); // Count property is used to get the // number of elements in ld Console.WriteLine(od.Count); } } Output: Before Add Method: 0 After Add Method: 4 Reference: https://learn.microsoft.com/en-us/dotnet/api/system.collections.specialized.ordereddictionary.-ctor?view=netframework-4.7.2#System_Collections_Specialized_OrderedDictionary__ctor Comment More infoAdvertise with us Next Article C# | How to create a SortedList K Kirti_Mangal Follow Improve Article Tags : C# CSharp-Specialized-Namespace CSharp-Specialized-OrderedDictionary Similar Reads How to create a ListDictionary in C# ListDictionary() constructor is used to initialize a new empty instance of the ListDictionary class using the default comparer. ListDictionary is a specialized collection. It comes under the System.Collections.Specialized namespace. This type represents a non-generic dictionary type. It is implement 2 min read How to create a StringDictionary in C# StringDictionary() constructor is used to initialize a new instance of the StringDictionary class which will be empty and will have the default initial capacity. StringDictionary is a specialized collection. This class comes under the System.Collections.Specialized namespace. It only allows string k 2 min read C# | Get a read-only copy of the OrderedDictionary OrderedDictionary.AsReadOnly method returns a read-only copy of the current OrderedDictionary collection. Syntax: public System.Collections.Specialized.OrderedDictionary AsReadOnly (); Return Value: A read-only copy of the current OrderedDictionary collection. Below given are some examples to unders 2 min read C# | How to create a SortedList SortedList class is a collection of (key, value) pairs which are sorted according to keys. Those pairs can be accessible by key and as well as by index(zero-based indexing). This comes under System.Collections namespace. Properties of SortedList: Internally the object of SortedList maintains two arr 2 min read C# | How to create a SortedSet SortedSet class represents the collection of objects in sorted order. This class comes under the System.Collections.Generic namespace. Properties : In C#, SortedSet class can be used to store, remove or view elements. It maintains ascending order and does not store duplicate elements. It is suggeste 2 min read C# OrderedDictionary Class In C#, the OrderedDictionary Class represents a collection of key/value pairs that are accessible by the key or index. It is present in System.Collections.Specialized namespace.It implements both IDicitonary and ICollection interfaces.Allows indexed access to elements via both keys and numeric index 6 min read Like