C# - Hashtable Class

using System;
using System.Collections;

public class ExampleHashtable
{
    public void exampleAdd()
    {
        Hashtable Ht = new Hashtable();

        Ht.Add(01, "This");
        Ht.Add(03, "is");
        Ht.Add(04, "my");
        Ht.Add(06, "system");
        int i = 0;
        foreach(var h in Ht)
        {
            Console.WriteLine("Ht["+ i + "] = " +Ht[i++]); 
        }
        ICollection ic;
        ic = Ht.Keys;
        foreach(var k in ic)
        {
            Console.WriteLine(k);
        }
        if (Ht.ContainsKey(04))
        {
            Console.WriteLine("Key found");
        }
        else
        {
            Console.WriteLine("Key not found");
        }
        if (Ht.ContainsValue("my"))
        {
            Console.WriteLine("value found");

        }
        else
        {
            Console.WriteLine("value not found");
        }
    }
}


namespace collectionHashtable
{
    class Program
    {
        static void Main(string[] args)
        {
            ExampleHashtable ht = new ExampleHashtable();
            ht.exampleAdd();
            Console.WriteLine("It Works");
         }
    }
}