Difference between Dictionary and Hashtable in C#

Hashtable is slower than Dictionary. For strongly-typed collections, the Dictionary collection is faster.

Hashtable

Hashtable class represents a collection of key-and-value pairs that are organized based on the hash code of the key. It uses the key to access the elements in the collection.

Let us see an example −

Example

 Live Demo

using System; using System.Collections; namespace Demo {    class Program {       static void Main(string[] args) {          Hashtable ht = new Hashtable();          ht.Add("E001", "Tom");          ht.Add("E098", "Amit");          ht.Add("E110", "Jack");          ICollection key = ht.Keys;          foreach (string k in key) {             Console.WriteLine(k + ": " + ht[k]);          }          Console.ReadKey();       }    } }

Output

E001: Tom E098: Amit E110: Jack

Dictionary

Dictionary is a collection of keys and values in C#. Dictionary<TKey, TValue> is included in the System.Collection.Generics namespace.

Example

 Live Demo

using System; using System.Collections.Generic; public class Demo {    public static void Main() {       IDictionary<int, int> dict = new Dictionary<int, int>();       dict.Add(1,234);       dict.Add(2,489);       dict.Add(3,599);       dict.Add(4,798);       dict.Add(5,810);       dict.Add(6,897);       dict.Add(7,909);       Console.WriteLine("Dictionary elements: "+dict.Count);    } }

Output

Dictionary elements: 7