arraylist

Question

hiiiiii
i have some doubt plz clear me.
.  Q. when adding a collection to the
array list, we are using AddRange, instead of Add. why it is? what is the need of AddRange?

Answer

http://www.dotnetperls.com/arraylist

Vulpes · Answer

There are two ways in which you can add a collection to an ArrayList:
1. You can use the Add method to add the collection object as a single element of the ArrayList. You can then access individual members of the collection in the following way:
ArrayList al = new ArrayList();   int[] ia = {1, 2, 3};   al.Add(ia);   int i = (al[0] as int[])[1]; // i == 2
2. You can use the AddRange method so that the individual elements of the collection become individual elements of the ArrayList:
al.AddRange(ia);   int i = (int)al[2]; // i == 3
Which you prefer will depend on whether you're trying to create a collection of collections (use Add) or a collection of some basic type such as int, double etc. from existing collections of that type (use AddRange).

Sanjeeb Lenka · Answer

hi,
AddRange adds an entire collection of elements. It can replace tedious foreach-loops that repeatedly call Add on List .
Add will add one item at a time.
ex:
using System;
using System.Collections.Generic;
class Program
{
static void Main()
{
List a = new List ();
a.Add(1);
a.Add(2);
a.Add(5);
a.Add(6);
// Contains:
// 1
// 2
// 5
// 6
int[] b = new int[3];
b[0] = 7;
b[1] = 6;
b[2] = 7;
a.AddRange(b);
// Contains:
// 1
// 2
// 5
// 6
// 7 [added]
// 6 [added]
// 7 [added]
foreach (int i in a)
{
Console.WriteLine(i);
}
}
}
Output
1
2
5
6
7
6
7