List Collection Class in C#

Introduction

A List is one of the generic collection classes in the "System.Collection.Generic" namespace. There are several generic collection classes in the System.Collection.Generic namespace that includes the following:

  1. Dictionary
  2. List
  3. Stack
  4. Queue

A List class can be used to create a collection of any type. For example, we can create a list of Integers, strings and even any complex types.

Why to use a List

  1. Unlike arrays, a List can grow in size automatically in other words a list can be re-sized dynamically but arrays cannot.
  2. List is a generic type.
  3. The List class also provides methods to search, sort and manipulate lists.

Example 1 - Using Array

I am taking an example to store data in an array and see what the problem is in storing the data in the array.

using System;  
using System.Collections.Generic;  
  
namespace List_Methods_Properties  
{  
    class Program  
    {  
        static void Main(string[] args)  
        {  
            customer customer1 = new customer()  
            {  
                EmpID = 1,  
                EmpName = "Sourabh",  
                EmpSalary = 50000  
            };  
            customer customer2 = new customer()  
            {  
                EmpID = 2,  
                EmpName = "Shaili",  
                EmpSalary = 60000  
            };  
            customer customer3 = new customer()  
            {  
                EmpID = 3,  
                EmpName = "Saloni",  
                EmpSalary = 55000  
            };  
            //Customer array
            customer[] customers = new customer[2];  
            customers[0] = customer1;  
            customers[1] = customer2;  
  
            //here I am adding one more cutomer to customers array and building the programs  
            customers[2] = customer3;  
        }  
    }  
    class customer  
    {  
        public int EmpID { get; set; }  
        public string EmpName { get; set; }  
        public int EmpSalary { get; set; }  
  
    }  
}  

In the example above I have created one class named "customer" and In the main method I have created an array named customers with a size of two. When I build this program (using CTRL+SHIFT+B) then I will get output like built successfully but when I run this program then I get the error:

When I run this program then at run time I will get the exception index was out of the bound of the array.

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Sourabh Somani
He is Microsoft MVP & C# Corner MVP. His core competencies include Mobile and web applications development using .NET, Python, Node.js, C#, JavaScript, jQuery, SQL Server, NoSQL, MongoDB, and Angular.
Chittorgarh, Rajasthan, India