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collection in asp.net c#

Collection represents a set of classes or objects that you can access to different type for different purpose. 

The name space of collection classes are

1. System. Collections
2. System.Collections.Generic

http://code-sample.net/images/collectionclasses%20.png

The System.Collection class contain the many classes for different purpose which explains in below.

  1. ArrayList
  2. Dictionary 
  3. HashTable 
  4. Stack
  5. Queue
ArrayList

Array List is collection with different data type using the System.Collection namespace. It is dynamic array and provides the feature for dynamic access.

http://code-sample.net/images/MethodsCollection.png

Example for Add() method

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

namespace CollectionClasses
{
  
               public class Program
               {
                               public static void ArrayListColl()
                               {
                                              ArrayList objArrayList = new ArrayList();
                                              objArrayList.Add("India");
                                              objArrayList.Add("Uttar Pradesh");
                                              objArrayList.Add("Kushinagar");

                                              foreach (string element in objArrayList)
                                              {
                                                             Console.WriteLine(element);
                                                             Console.ReadLine();
                                              }
                               }
                               static void Main(string[] args)
                               {
                                              ArrayListColl();
                               }
               }
}

Output

http://code-sample.net/images/ArrListAddOutput.png
Again another example for RemoveAt() method

Remove the records with help of specific index.
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace CollectionClasses
{
  
               public class Program
               {
                               public static void ArrayListColl()
                               {
                                              ArrayList objArrayList = new ArrayList();
                                              objArrayList.Add("India");
                                              objArrayList.Add("Uttar Pradesh");
                                              objArrayList.Add("Kushinagar");
                                              objArrayList.RemoveAt(1);
                                              foreach (string element in objArrayList)
                                              {
                                                             Console.WriteLine(element);
                                                             Console.ReadLine();
                                              }
                               }
                              
                               static void Main(string[] args)
                               {
                                              ArrayListColl();
                               }
               }
}
Output
In the above example, remove the string from the Array List at index 1. So output is below.
http://code-sample.net/images/ArrListRemoveAtOutput.png
Again another example for Remove () method
Remove the records with help of specific object.
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace CollectionClasses
{
  
               public class Program
               {
                               public static void ArrayListColl()
                               {
                                              ArrayList objArrayList = new ArrayList();
                                              objArrayList.Add("India");
                                              objArrayList.Add("Uttar Pradesh");
                                              objArrayList.Add("Kushinagar");
                                              objArrayList.Remove("Kushinagar");
                                              foreach (string element in objArrayList)
                                              {
                                                             Console.WriteLine(element);
                                                             Console.ReadLine();
                                              }
                               }
                              
                              static void Main(string[] args)
                               {
                                              ArrayListColl();
                               }
               }
}
OutPut :

http://code-sample.net/images/ArrListRemoveOutput.png
Again another example for Insert () method

Insert the records with help of specific index.
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace CollectionClasses
{
  
               public class Program
               {
                               public static void ArrayListColl()
                               {
                                              ArrayList objArrayList = new ArrayList();
                                              objArrayList.Insert(0,"India");
                                              objArrayList.Insert(1,"Uttar Pradesh");
                                              objArrayList.Insert(2,"Kushinagar");
                                             
                                              foreach (string element in objArrayList)
                                              {
                                                             Console.WriteLine(element);
                                                             Console.ReadLine();
                                              }
                               }
                              
                               static void Main(string[] args)
                               {
                                              ArrayListColl();
                               }
               }
}
                                             
OupPut

http://code-sample.net/images/ArrListInsertOutput.png
Dictionary
The Dictionary collection class is a generic class that contain the any data type. The Dictionary class contain two parameters (generic type) one is key and other is value. Before implementation, we must import the System.Collections.Generic namespace. The dictionary type provides fast searching with key to get its values. Dictionary is used when we have different elements. The Dictionary contains the some different feature.
http://code-sample.net/images/dictionaryColliection.png
Syntax :
Dictionary objDict=new Dictionary();
Example for Add, ContainsKey and ContainsValue
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace CollectionClasses
{
  
               public class Program
               {
                               public static void DictionaryMethod()
                               {
                                              Dictionary objDict=new Dictionary();
                                              objDict.Add("India",1);
                                              objDict.Add("UP",2);
                                              objDict.Add("Kushinagar",3);
                                                            
                                              if (objDict.ContainsKey("India"))
                                              {
                                                             dynamic text = objDict["India"];
                                                             Console.WriteLine(text);
                                                             Console.ReadLine();
                                              }

                                              if (objDict.ContainsValue(1))
                                              {
                                                             Console.WriteLine("India");
                                                             Console.ReadLine();
                                              }

                               }
                               static void Main(string[] args)
                               {
                                              DictionaryMethod();
                               }
               }
}

OutPut :

http://code-sample.net/images/dictionaryAdd.png
Another example for dictionary KeyValuePair objects
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace CollectionClasses
{
  
               public class Program
               {
                               public static void KeyValuePair()
                               {
                                              dynamic keyValList = new List>();
                                              keyValList.Add(new KeyValuePair("India", 1));
                                              keyValList.Add(new KeyValuePair("UP", 2));
                                              keyValList.Add(new KeyValuePair("Kushinagar", 4));

                                              foreach (var element in keyValList)
                                              {
                                                             Console.WriteLine(element);
                                                             Console.ReadLine();
                                              }
                               }
                               static void Main(string[] args)
                               {
                                              KeyValuePair();
                               }
               }
}

OutPut :

http://code-sample.net/images/KeyValuePair.png
Another example for KeyValuePair

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

namespace CollectionClasses
{
               public class Program
               {
                               public static void KeyValuePair()
                               {
                                              Dictionary keyValList = new Dictionary();

                                              keyValList.Add("India", 1);
                                              keyValList.Add("UP", 2);
                                              keyValList.Add("Kushinagar", 4);

                                              foreach (KeyValuePair element in keyValList)
                                              {
                                                             Console.WriteLine("key = {0}, value = {1}", element.Key,element.Value);
                                                            
                                              }
                                              Console.ReadKey();
                               }
                               static void Main(string[] args)
                               {
                                              KeyValuePair();
                               }
               }
}


OutPut :

http://code-sample.net/images/KeyValuePairSecond.png

HashTable
HashTable is a collection classes which provide the support to key base searching and stored the key value pair type collection data. HashTable searching the element is very fast but slower then generic Dictionary type. In HashTable we can maintain the data uniqueness that means without having null values and duplicate value. In HashTable, both key and value is object and we can retrieve the items from the HashTable by providing the key.
Syntax :
Hashtable objHash=new Hashtable();
HashTable contain the methods which are give below in
http://code-sample.net/images/HashTable.png
Simple example of HashTable

Simple example of HashTable

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

namespace CollectionClasses
{
  
               public class Program
               {
                               public static void HashTableMethod()
                               {
                                  Hashtable objHash=new Hashtable();
                                  objHash.Add("India", 1);
                                  objHash.Add("UP", 2);
                                  objHash.Add("Kushinagar", 4);

                                  foreach (DictionaryEntry element in objHash)
                                              {
                                                             Console.WriteLine("key = {0}, value = {1}", element.Key,element.Value);
                                                            
                                              }
                                              Console.ReadKey();
                               }
                               static void Main(string[] args)
                               {
                                              HashTableMethod();
                               }
               }
}

OutPut :

http://code-sample.net/images/HashTableOutput.png
AAnother example to get the keys using HashTable

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

namespace CollectionClasses
{
  
               public class Program
               {
                               public static void HashTableMethod()
                               {
                                  Hashtable objHash=new Hashtable();
                                  objHash.Add("India", 1);
                                  objHash.Add("UP", 2);
                                  objHash.Add("Kushinagar", 4);

                                              IDictionaryEnumerator objDe = objHash.GetEnumerator();
                                              while (objDe.MoveNext())
                                              {
                                                             string result = objDe.Key.ToString();
                                                             Console.WriteLine(result);
                                              }
                                              Console.ReadKey();
                               }
                               static void Main(string[] args)
                               {
                                              HashTableMethod();
                               }
               }
}

OutPut :

http://code-sample.net/images/HashTableOutput1.png
Another example to get the values using HashTable

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

namespace CollectionClasses
{  
               public class Program
               {
                               public static void HashTableMethod()
                               {
                                  Hashtable objHash=new Hashtable();
                                  objHash.Add("India", 1);
                                  objHash.Add("UP", 2);
                                  objHash.Add("Kushinagar", 4);

                                              IDictionaryEnumerator objDe = objHash.GetEnumerator();
                                              while (objDe.MoveNext())
                                              {
                                                             string result = objDe.Value.ToString();
                                                             Console.WriteLine(result);
                                              }
                                              Console.ReadKey();
                               }
                               static void Main(string[] args)
                               {
                                              HashTableMethod();
                               }
               }
}

OutPut :

http://code-sample.net/images/HashTableOutput2.png
Stack
Stack is a Last-In-First-Out collection that is called LIFO. Stack is a generic type collection. Stack worked on two basic components which are 1. Push 2. Pop Push is formally worked for insert an item on the top in stack. Pop is formally worked on the remove the last inserted record from the stack.

Example for Push
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace CollectionClasses
{
  
               public class Program
               {
                               public static Stack StackMethod()
                               {
                                              Stack objStack = new Stack();
                                              objStack.Push(1);
                                              objStack.Push(10);
                                              objStack.Push(100);
                                              objStack.Push(1000);
                                              objStack.Push(10000);
                                              return objStack;
                               }
                               static void Main(string[] args)
                               {
                                              dynamic stack= StackMethod();
                                              foreach (int item in stack)
                                              {
                                                             Console.WriteLine(item);
                                              }
                                              Console.ReadLine();
                               }
               }
}

OutPut :

http://code-sample.net/images/Stack1.png
Another example for Pop
namespace CollectionClasses
{
               public class Program
               {
                               public static Stack StackMethod()
                               {
                                              Stack objStack = new Stack();
                                              objStack.Push(1);
                                              objStack.Push(10);
                                              objStack.Push(100);
                                              objStack.Push(1000);
                                              objStack.Push(10000);
                                              return objStack;
                               }
                               static void Main(string[] args)
                               {
                                              Stack stack= StackMethod();
                                              int pop= stack.Pop();
                                              Console.WriteLine(pop);
                                              Console.ReadLine();
                               }
               }
}

OutPut :

http://code-sample.net/images/Stack2.png
Example using Push, Pop and Peek
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace CollectionClasses
{
               public class Program
               {
                               public static Stack StackMethod()
                               {
                                              Stack objStack = new Stack();
                                              objStack.Push(1);
                                              objStack.Push(10);
                                              objStack.Push(100);
                                              objStack.Push(1000);
                                              objStack.Push(10000);
                                              return objStack;
                               }
                               static void Main(string[] args)
                               {
                                              Stack stack= StackMethod();

                                              Console.WriteLine("Display the Stack");
                                              foreach (int i in stack)
                                              {
                                                             Console.WriteLine(i);
                                              }

                                              int pop = stack.Pop();
                                              Console.WriteLine("pop the element from the stack!");
                                              Console.WriteLine(pop);

                                              int peek= stack.Peek();
                                              Console.WriteLine("peek the element from the stack!");
                                              Console.WriteLine(peek);
                                              Console.ReadLine();
                               }
               }
}
The Output as given below
http://code-sample.net/images/Stack3.png
Queue
Queue is First-In-First-Out collection that is classed FIFO. Queue is a generic collection. Queue provides the First - come first- service.
Example
 using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace CollectionClasses
{
               public class Program
               {
                               public static Queue QueueMethod()
                               {
                                              // Add integers to queue.
                                              Queue objQueue = new Queue();
                                              objQueue.Enqueue(1);
                                              objQueue.Enqueue(10);
                                              objQueue.Enqueue(100);
                                              objQueue.Enqueue(1000);

                                              // Loop through queue.
                                              foreach (int i in objQueue)
                                              {
                                                             Console.WriteLine(i);
                                              }
                                              return objQueue;
                               }
                               static void Main(string[] args)
                               {
                                              Queue queu = QueueMethod();
                                              Console.WriteLine(queu);
                                              Console.ReadLine();
                               }
               }
}


The Output as given below
http://code-sample.net/images/Queu.png

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