C# - SPLessons

How to use C# HashTable Class

SPLessons 5 Steps, 3 Clicks
5 Steps - 3 Clicks

How to use C# HashTable Class

How to use C# HashTable Class

Description :

Hi Friends, let me give you a intro about How to use C# HashTable Class. It is a collection with key and value as a pair. Object are organized based on the hash code of the key. It is easy to perform action like Add, Delete, Search, etc. using key as Index of the list.

 

Namespace :

using System.Collections;

Step1 :

Please open visual studio, right now i have visual studio 2013 i just opened my visual studio and click on new project.

Step2 :

In the new project window please click on templates visual c# and then click on windows  and on the right side panel just click on console application. Please give a name for the console application and click ok button.

Step3 :

If you see the visual studio will gives you a predefined template program  for us.

Step4 :

Lets, Build simple console application to Add, Delete, Find value with key, Find value with value and Display items from HashTable.

Main Method :
class Program
 {
 public static Hashtable hashtable = new Hashtable();
 public static Boolean flag = true;
 static void Main(string[] args)
 {
 while (flag)
 {
 Console.WriteLine("\n1. Insert \t\t2. Remove \n3. Find value with key \t4. Find value with value\n5. Display\t\t6. Exit");
 Console.Write("Please enter your Choice: ");
 string choice = Console.ReadLine();
 switch (choice)
 {
 case "1":
 hashtable = Insert(hashtable);
 break;
 case "2":
 hashtable = Remove(hashtable);
 break;
 case "3":
 FindValueUsingKey(hashtable);
 break;
 case "4":
 FindValueUsingValue(hashtable);
 break;
 case "5":
 Display(hashtable);
 break;
 case "6":
 flag = false;
 break;
 default:
 Console.WriteLine("Enter correct choice !!");
 break;
 }
 }
 }


Output :


Insert :

private static Hashtable Insert(Hashtable hashtable)
 {
 Console.Write("Please enter data into HashTable.\nKey : ");
 string key = Console.ReadLine();
 Console.Write("Value : ");
 string value = Console.ReadLine();
 hashtable.Add(key, value);
 Display(hashtable);
 return hashtable;
 }


Output :


Remove :

private static Hashtable Remove(Hashtable hashtable)
 {
 Console.Write("Please enter data to delete from HashTable.\nKey : ");
 string key = Console.ReadLine();
 hashtable.Remove(key);
 Display(hashtable);
 return hashtable;
 }


Output :


Finding Value using Key :

private static void FindValueUsingKey(Hashtable hashtable)
 {
 Console.Write("Please enter data to find value in HashTable.\nKey : ");
 string key = Console.ReadLine();
 Boolean flag = hashtable.ContainsKey(key);
 if(flag)
 {
 Console.WriteLine(key + " have a Value in HashTable.");
 }
 else
 {
 Console.WriteLine(key + " doesn't have any Value in HashTable.");
 }
 }


Output :


Finding Value using Value :

private static void FindValueUsingValue(Hashtable hashtable)
 {
 Console.Write("Please enter data to find value in HashTable.\nValue : ");
 string value = Console.ReadLine();
 Boolean flag = hashtable.ContainsValue(value);
 if (flag)
 {
 Console.WriteLine(value + " is there in HashTable.");
 }
 else
 {
 Console.WriteLine(value + " is not there in HashTable.");
 }
 }


Output :


Display :

private static void Display(Hashtable hashtable)
 {
 var item = hashtable.GetEnumerator();
 while(item.MoveNext())
 {
 Console.WriteLine(item.Key + "\t: " + item.Value);
 }
 }


Output :

Other Function :

There are many other function which you can try.


Keys :
Gets an ICollection containing the keys in the Hashtable.


Values :
Gets an ICollection containing the values in the Hashtable.


Contains :
Determines whether the Hashtable contains a specific key.


CopyTo :
Returns an Hashtable to an existing one-dimensional Array.


Clear :
Removes all elements from the Hashtable.
etc.


Enjoy to Code..;)