C#: System.Collections.Hashtable

gistfile1.cs

using System;
using System.Collections;

namespace HashtableExample {
    class Program {
        static void Main(string[] args) {

            // Create a new hashtable
            Hashtable genericDomains = new Hashtable();

            // Add values to the hashtable
            genericDomains.Add( "com", "Commercial Organizations" );
            genericDomains.Add( "net", "Network Infrastructures" );
            genericDomains.Add( "org", "Organization" );
            genericDomains.Add( "gov", "U.S. Government" );

            // Access values by the default Item property
            Console.WriteLine( "For key \"com\" the value is \"{0}\".", genericDomains["com"] );
            Console.WriteLine( "For key \"org\" the value is \"{0}\".", genericDomains["org"] );

            // Change a value by the default Item property
            genericDomains["com"] = "Commercial Organizations, but unrestricted";
            Console.WriteLine( "For key \"com\" the value is \"{0}\".", genericDomains["com"] );

            // Add a new key/value pair
            genericDomains["edu"] = "Post-Secondary Educational Establishments";

            // Use ContainsKey to test keys before inserting them
            if ( !genericDomains.ContainsKey( "mil" ) ) {
                genericDomains.Add( "mil", "U.S. Military" );
                Console.WriteLine( "Value added for key = \"mil\": {0}", genericDomains["mil"] );
            }

            // Enumerate hashtable KeyValuePair objects
            Console.WriteLine();
            foreach ( DictionaryEntry de in genericDomains ) {
                Console.WriteLine( "Key = {0}, Value = {1}", de.Key, de.Value );
            }

            // Use the Values property to get just the values
            ICollection valueColl = genericDomains.Values;
            Console.WriteLine();
            foreach ( string s in valueColl ) {
                Console.WriteLine( "Value = {0}", s );
            }

            // Use the Keys property to get just the keys
            ICollection keyColl = genericDomains.Keys;
            Console.WriteLine();
            foreach ( string s in keyColl ) {
                Console.WriteLine( "Key = {0}", s );
            }

            // Use the Remove method to remove a key/value pair
            Console.WriteLine( "\nRemove(\"net\")" );
            genericDomains.Remove( "net" );

            // Test the keys for the removed key
            if ( !genericDomains.ContainsKey( "net" ) ) {
                Console.WriteLine( "Key \"net\" is not found." );
            }

            Console.Read();
        }
    }
}