C# hashtable

C# Hashable is a collection class that can be used to store pairs of key/value. When storing in the Hashtable object, key and value are converted to object type automatically. The most commonly used methods and properties of the Hashtable are :
-Add(object key, object value)
-Remove(object key)
-Clear()
-Keys
-Values
-CopyTo(Array array, int start_index)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Collections;

namespace Csharp_tip
{

   class Program
   {
    
     static void Main(string[] args)
     {
        //create Hashtable object
        Hashtable hb = new Hashtable();
        //Add key/value pairs to the Hashtable object
        try //catch key exist error
        {
           hb.Add("c1", "Canada");
           hb.Add("c2", "USA");
           hb.Add("c3", "Autralia");
          
        }
        catch (ArgumentException ae) { Console.WriteLine(ae.ToString() ); }
        //Read all values in the Hastable object using key
        foreach (object key in hb.Keys)
        {
           Console.WriteLine(hb[key].ToString());
        }
        //an alternative to read all values is using values collection property
        foreach (object value in hb.Values)
        {
           Console.WriteLine(value.ToString());
        }
        //count all pairs of key and value
        Console.WriteLine("Number of key/value pairs:{0}",hb.Count );
        
        //key checking
        if (hb.ContainsKey("c3"))
        {
           Console.WriteLine("This key exists.");
        }
        //Copy all values to an array
        object []arrval=new object[hb.Count ];
        hb.Values.CopyTo(arrval, 0);
        //Copy all keys to an array
        object[] arrkey = new object[hb.Count];
        hb.Keys.CopyTo(arrkey, 0);

        //Remove a specific pair of key/value using key
        hb.Remove("c3");

        //Remove all pairs in the Hashtable object
        hb.Clear();
        

        Console.Read();

     }
}
}

Posted by: Lavy | post date: 01-28-2013 | Subject: C# Programming Language




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