c# arraylist

                                    using System.Collections;

ArrayList arlist = new ArrayList(); 
// or 
var arlist = new ArrayList(); // recommended 

                                    ArrayList arrList = new ArrayList()

                                    var arlist1 = new ArrayList();

var arlist2 = new ArrayList()
                    {
                        1, "Bill", " ", true, 4.5, null
                    };

int[] arr = { 100, 200, 300, 400 };

Queue myQ = new Queue();
myQ.Enqueue("Hello");
myQ.Enqueue("World!");

arlist1.AddRange(arlist2); //adding arraylist in arraylist 
arlist1.AddRange(arr); //adding array in arraylist 
arlist1.AddRange(myQ); //adding Queue in arraylist 

                                    // adding elements using ArrayList.Add() method
var arlist1 = new ArrayList();
arlist1.Add(1);
arlist1.Add("Bill");
arlist1.Add(" ");
arlist1.Add(true);
arlist1.Add(4.5);
arlist1.Add(null);

// adding elements using object initializer syntax
var arlist2 = new ArrayList()
                {
                    2, "Steve", " ", true, 4.5, null
                };