How to use C# ArrayList Class
ArrayList is one of the most flexible data structure from CSharp Collections. ArrayList contains a simple list of values. ArrayList implements the IList interface using an array and very easily we can add , insert , delete , view etc. It is very flexible because we can add without any size information , that is it will grow dynamically and also shrink .
Add : Add an Item in an ArrayList
Insert : Insert an Item in a specified position in an ArrayList
Remove : Remove an Item from ArrayList
RemoveAt: remove an item from a specified position
Sort : Sort Items in an ArrayList
How to add an Item in an ArrayList ?
Syntax : ArrayList.add(object)
object : The Item to be add the ArrayList
ArrayList arr;
arr.Add("Item1");
How to Insert an Item in an ArrayList ?
Syntax : ArrayList.insert(index,object)
index : The position of the item in an ArrayList
object : The Item to be add the ArrayList
ArrayList arr;
arr.Insert(3, "Item3");
How to remove an item from arrayList ?
Syntax : ArrayList.Remove(object)
object : The Item to be add the ArrayList
arr.Remove("item2")
How to remove an item in a specified position from an ArrayList ?
Syntax : ArrayList.RemoveAt(index)
index : the position of an item to remove from an ArrayList
ItemList.RemoveAt(2)
How to sort ArrayList ?
Syntax : ArrayList.Sort()
The following CSharp source code shows some function in ArrayList
using System;
using System.Collections;
using System.Windows.Forms;
namespace WindowsApplication1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
int i = 0;
ArrayList ItemList = new ArrayList();
ItemList.Add("Item4");
ItemList.Add("Item5");
ItemList.Add("Item2");
ItemList.Add("Item1");
ItemList.Add("Item3");
MessageBox.Show ("Shows Added Items");
for (i = 0; i < = ItemList.Count - 1; i++)
{
MessageBox.Show(ItemList[i].ToString());
}
//insert an item
ItemList.Insert(3, "Item6");
//sort itemms in an arraylist
ItemList.Sort();
//remove an item
ItemList.Remove("Item1");
//remove item from a specified index
ItemList.RemoveAt(3);
MessageBox.Show("Shows final Items the ArrayList");
for (i = 0; i < = ItemList.Count - 1; i++)
{
MessageBox.Show(ItemList[i].ToString());
}
}
}
} |
When you execute this C# program , at first add five items in the arraylist and displays. Then again one more item inserted in the third position , and then sort all items. Next it remove the item1 and also remove the item in the third position . Finally it shows the existing items.
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