The Hashtable class represents a series of key/value pairs organized by key-based hash code. It uses keys to access elements in the collection.
When you use keys to access elements, a hash table is used, and you can identify a useful key value. Each item in the hash table has a key/value pair. Key is used to access items in the collection. The following table lists some common properties of Attribute Description Count Gets the number of key-value pairs contained in Hashtable. IsFixedSize Gets a value indicating whether the Hashtable has a fixed size. IsReadOnly Gets a value indicating whether the Hashtable is read-only. Item Gets or sets the value associated with the specified key. Keys Gets an ICollection containing the keys in the Hashtable. Values Gets an ICollection that contains the value in the Hashtable. The following table lists some common methods of Serial number Method name & description 1 Public virtual void Add (object key, object value); adds an element with thespecified key and value to Hashtable. 2 Public virtual void Clear (); removes all elements from the Hashtable. 3 Public virtual bool ContainsKey (object key); determines whether the Hashtable contains the specified key. 4 Public virtual bool ContainsValue (object value); determines whether the Hashtable contains the specified value. 5 Public virtual void Remove (object key); removes the element with the specified key from the Hashtable. The following example demonstrates the concept of a Hashtable: When the above code is compiled and executed, it produces the following results: 1.55.1. Methods and properties of the Hashtable class #
Hashtable class: Hashtable :Example #
1.55.2. Example #
using System; using System.Collections; namespace CollectionsApplication { class Program { static void Main(string[] args) { Hashtable ht = new Hashtable(); ht.Add("001", "Zara Ali"); ht.Add("002", "Abida Rehman"); ht.Add("003", "Joe Holzner"); ht.Add("004", "Mausam Benazir Nur"); ht.Add("005", "M. Amlan"); ht.Add("006", "M. Arif"); ht.Add("007", "Ritesh Saikia"); if (ht.ContainsValue("Nuha Ali")) { Console.WriteLine("This student name is already in the list"); } else { ht.Add("008", "Nuha Ali"); } // Get a collection of keys ICollection key = ht.Keys; foreach (string k in key) { Console.WriteLine(k + ": " + ht[k]); } Console.ReadKey(); } } }
007: Ritesh Saikia 004: Mausam Benazir Nur 005: M. Amlan 008: Nuha Ali 002: Abida Rehman 003: Joe Holzner 001: Zara Ali 006: M. Arif