Hashtable becomes serialized

using System;
using System.Collections;
using System.Runtime.Serialization.Formatters.Binary;
using System.IO;

namespace Hashtable_Serialized
{
	//Two structs are represented here, we save them both in the hashtable
	//note that each struct attributed as serializable, which means we can serialize the exact
	//data form (struct) into a serialize stream
	[Serializable]
	struct name
	{
		public string forname;
		public string familyname;
	}

	[Serializable]
	struct address
	{
		public string street;
		public int number;
	}
   
	//this is the main class for manipulating the hashtable
	class clsDataBlock
	{
		//this is our hashtable variable, a global one.
		public static Hashtable       NameToAddress = new Hashtable ();   

		[STAThread]
		static void Main(string[] args)
		{
			clsDataBlock db=new clsDataBlock ();
			string ans=""; //answer string
			while("x" != ans) //here we write a menu to the console
			{
				System.Console.WriteLine ("1 to enter new");
				System.Console.WriteLine ("2 to search");
				System.Console.WriteLine ("3 to save (serialize)");
				System.Console.WriteLine ("4 to load (deserialize)");
				System.Console.WriteLine ("5 to show data");
				System.Console.WriteLine ("x to quit");
				System.Console.WriteLine ("-----------------------");
				ans = System.Console.ReadLine (); //and real the selection
			switch(ans)
				{
					//we call the wanted function here
					case "1":db.AddNew();
						break;
					case "2":db.Search();
						break;
					case "3":db.Save();
						break;
					case "4":db.Load();
						break;
					case "5":db.Show();
						break;
				}
			}
		}

		//A method to add new object to the hashtable,
		//we create a struct of name and address, fill it and save it in hash
		public void AddNew()
		{
			name nm; //name struct
			address ad; //address struct
			string ans; //answer string

			//we then ask info from the user and insert that info to our structs
			System.Console.WriteLine ("enter first name (x to exit):");
			ans = System.Console.ReadLine();
			nm.forname = ans;
			System.Console.WriteLine ("enter last name (x to exit):");
			ans = System.Console.ReadLine();
			nm.familyname = ans;
 			System.Console.WriteLine ("enter street name (x to exit):");
			ans = System.Console.ReadLine();
			ad.street = ans;
			System.Console.WriteLine ("enter street number (x to exit):");
			ans = System.Console.ReadLine();
			ad.number = int.Parse (ans);

			//now we save the new object into the hashtable, the key here is the name struct
			NameToAddress.Add(nm,ad);
		}

		//this method asks for the key struct, which is the name, and searches the hashtable
		public void Search()
		{
			name nm2;
			string ans2;
			System.Console.WriteLine ("enter first name:");
			ans2 = System.Console.ReadLine ();
			nm2.forname = ans2;
			System.Console.WriteLine ("enter last name:");
			ans2 = System.Console.ReadLine ();
			nm2.familyname  = ans2;
			System.Console.WriteLine ("working...");

			//here we ask for the struct from the hashtable, given the name object
			object sname = NameToAddress[nm2];
			if (sname != null)
			{
				address ad2 = (address)sname;
				System.Console.WriteLine(" address: "+ ad2.street + " " + ad2.number );
			}
			//none found
			else System.Console.WriteLine ("no name like that...");
		}


		//this method serialize the hashtable into a binary file, 
		//we have a load function to load that exact saved file
		public void Save()
		{
			//file stream states the saved binary
			FileStream fs = new FileStream ("Store.dat",FileMode.OpenOrCreate ,FileAccess.Write );
			try
			{
				Hashtable a = new Hashtable();
				a = NameToAddress;
				BinaryFormatter bf=new BinaryFormatter ();
				//as easy as 1,2,3...we serialize a to a binary formating using file stream.
				bf.Serialize (fs,a );
			}
			finally
			{
				fs.Close ();
			}
		}

		//A method to load saved binary file
		public void Load()
		{
			FileStream fs = new FileStream ("Store.dat",FileMode.Open ,FileAccess.Read );

			try
			{
				Hashtable a = new Hashtable();
				BinaryFormatter bf=new BinaryFormatter ();

				//here we deserialize the binary to a hashtable
				a=(Hashtable)bf.Deserialize (fs);
				NameToAddress = a;
			}
			finally
			{
				fs.Close ();
			}
		}

		//A method to iterate around all values in hashtable and print them
		public void Show()
		{
			name nm3;
			address ad3;

			//for each is used in Dictionary entry 
			foreach (DictionaryEntry entry in NameToAddress )
			{
				nm3 = (name)entry.Key;
				ad3 = (address)entry.Value;
				Console.WriteLine ("name= {0} {1}, address= {2} {3}", nm3.forname,nm3.familyname ,ad3.street ,ad3.number);
			}
		}
	}
}