In this blog we will find Duplicate Records present in ArrayList and display those to a listbox.

using System;
using
System.Collections.Generic;
using
System.ComponentModel;
using
System.Data;
using
System.Drawing;
using
System.Linq;
using
System.Text;
using
System.Windows.Forms;
using
System.Collections;
namespace
Duplicate_Records_in_ArrayList
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

private void Form1_Load(object sender, EventArgs e)
{
var list = new ArrayList { "Raj", "Raj", "Ravi", "Rahul", "Ravi", "Rohan", "Rajesh", "Rahul" };
var clone =
(from string item in list select item).GroupBy(s => s).Select(
group => new { Word = group.Key, Count = group.Count() }).Where(x => x.Count >=
2);

foreach (var duplicate in clone)
{
listBox1.Items.Add(duplicate.Word);
}

}
}
}