Practical Approach of Adding, Removing and Inserting Item Using Generic List<T>

Now let's see how to do various types of mechanisms like adding, removing and inserting.

1. How to Add an item to the generic List<T>?
   
   /// <summary>
   /// This is static collection used in this tutorials
   /// </summary>
   /// <returns></returns>

   
   private static List<CompanyProduct> AddCollection()

   {

   List<CompanyProduct> list = new List<CompanyProduct>();

   list.Add(new CompanyProduct("MS Word", 1, "Microsoft", new DateTime(2012, 10, 31)));

   list.Add(new CompanyProduct("MS Excel", 2, "Microsoft", new DateTime(2011, 10, 31)));

   list.Add(new CompanyProduct("MS Powerpoint", 3, "Microsoft", new DateTime(2010, 10, 31)));

   list.Add(new CompanyProduct("Visual Studio", 2, "Microsoft", new DateTime(2011, 10, 31)));

   list.Add(new CompanyProduct("Sql Server", 3, "Microsoft", new DateTime(2010, 10, 31)));

   list.Add(new CompanyProduct("Oracle", 4, "Oracle", new DateTime(2011, 10, 31)));

   DisplayingList(list, "List of COllection");

   return list;

   }
   

2. How to Add or Append Items to the existing generic List<T>?
   
   /// <summary>

   /// This is used to add items to collection at once.

   /// </summary>

   private static void AppendingItems()

   {

   List<CompanyProduct> list = new List<CompanyProduct>();

   list.Add(new CompanyProduct("Sharepoint", 6, "Microsoft", new DateTime(2012, 10, 31)));

   list.Add(new CompanyProduct("MS Outlook", 7, "Microsoft", new DateTime(2011, 10, 31)));

   List<CompanyProduct> existingItems = AddCollection();

   existingItems.AddRange(list);

   //Display all the appended items.

   DisplayingList(existingItems, "Displaying Appending Item at once");

   }
   

3. How to Add or Append a Collection of items to an existing generic List<T>?
   
   /// <summary>

   /// This is used to add one by one item.

   /// </summary>

   private static void AppendingItem()

   {

   List<CompanyProduct> existingItems = AddCollection();

   existingItems.Add(new CompanyProduct("Yahoo WebBlog", 4, "Yahoo", new DateTime(2012, 10, 31)));

   DisplayingList(existingItems, "Displaying Appending Item one by one");

   }
   

4. How to Remove an item from the generic List<T>?
   
   /// <summary>

   /// Removes the specified Single item from the list.

   /// </summary>

   private static void RemoveItem()

   {
   CompanyProduct removeSharepoint = new CompanyProduct("Sharepoint", 6, "Microsoft", new DateTime(2012, 10, 31));
   CompanyProduct removeOutlook = new CompanyProduct("MS Outlook", 7, "Microsoft", new DateTime(2011, 10, 31));

   //Existing Items

   List<CompanyProduct> existingItems = AddCollection();

   //It removes the sharepoint product from list.So whatever companyProduct you sends

   // it just remove from the list.

   existingItems.Remove(removeSharepoint);

   existingItems.Remove(removeOutlook);

   DisplayingList(existingItems, "Removing Item one by one");

   }
   

5. How to Remove the specific item from the generic List<T>?
   
   /// <summary>

   /// Removes the specified item by index.

   /// </summary>

   private static void RemoveSpecificItem()

   {

   //Existing Items

   List<CompanyProduct> existingItems = AddCollection();

   //It removes the sharepoint product from list.So whatever companyProduct you sends

   // it just remove from the list.

   existingItems.RemoveAt(1); // Removed MS Word

   existingItems.RemoveAt(3); // Removed MS PowerPoint

   DisplayingList(existingItems, "Removing Item one by one");

   }
   

6. How to Remove the range of items from the generic List<T>?
   
   /// <summary>

   /// This is used to remove the specific range of items

   /// </summary>

   private static void RemoveSpecificRangeOfItems()

   {

   List<CompanyProduct> existingItems = AddCollection();

   //it removes first item from the list.

   existingItems.RemoveRange(1, 1);

   //it starts from second element and remove 2nd and 3rd item form the list.

   existingItems.RemoveRange(2, 2);

   DisplayingList(existingItems, "Removed Items");

   }
   

7. How to Clear items from the generic List<T>?
   
   /// <summary>

   /// This is used to remove all the elements form the list.

   /// </summary>

   private static void CleareAllItem()

   {

   List<CompanyProduct> existingItems = AddCollection();

   existingItems.Clear();

   Console.WriteLine("count of List=", existingItems.Count);

   }
   

8. How to Insert an item to the Generic List<T>?
   
   /// <summary>

   /// This is used to insert item at the last of collection.

   /// </summary>

   private static void InsertItem()

   {

   CompanyProduct addnotepad = new CompanyProduct("Notepad ", 7, "Unknown",

   new DateTime(2011, 10, 31));

   //Existing Items

   List<CompanyProduct> existingItems = AddCollection();

   //Inserted the norepad product at index 1.

   existingItems.Insert(1, addnotepad);

   DisplayingList(existingItems, "Displaying Inserted Item");

   }
   

9. How to Insert items at a specified range to the Generic List<T>?
   
   /// <summary>

   /// This is used to insert item at specified range.

   /// </summary>

   private static void InsertRangeItem()

   {

   List<CompanyProduct> list = new List<CompanyProduct>();

   list.Add(new CompanyProduct("LinqPad", 1, "Unknown",

   new DateTime(2012, 10, 31)));

   list.Add(new CompanyProduct("Silverlight", 2, "Microsoft",

   new DateTime(2011, 10, 31)));

   //Existing Items

   List<CompanyProduct> existingItems = AddCollection();

   //Inserted the norepad product at index 1.

   existingItems.InsertRange(3, list);

   DisplayingList(existingItems, "Displaying Inserted Collection");

   }

Note: Download the source and debug the code, it helps to understand the exact operations with the List.

Thanks for reading this article. Have a nice day.