Many time we need to use sorting with our objects of custom classes.

Here I have given an example of how to sort an Person class on the basis of its attribute by implementing IComparable interface.

using System;

//Add refrence to Collections namespace
using System.Collections;

class Inventory : IComparable
{
string name;
double cost;
int onhand;

public Inventory(string n, double c, int h)
{
name = n;
cost = c;
onhand = h;
}

//Overriding the ToString() method to show the output formatted
public override string ToString()
{
return
String.Format("{0,-10}Cost: {1,6:C} On hand: {2}", name, cost, onhand);
}

// Implement the IComparable interface.
public int CompareTo(object obj)
{
Inventory b;
b = (Inventory)obj;
return name.CompareTo(b.name);
}
}

public class IComparableDemo
{
public static void Main()
{
ArrayList inv = new ArrayList();

// Add elements to the list
inv.Add(new Inventory("Pliers", 5.95, 3));
inv.Add(new Inventory("Wrenches", 8.29, 2));
inv.Add(new Inventory("Hammers", 3.50, 4));
inv.Add(new Inventory("Drills", 19.88, 8));
Console.WriteLine("Inventory list before sorting:");

foreach (Inventory i in inv)
{
Console.WriteLine(" " + i);
}
Console.WriteLine();

// Sort the list.
inv.Sort();
Console.WriteLine("Inventory list after sorting:");

foreach (Inventory i in inv)
{
Console.WriteLine(" " + i);
}
}
}

Happy coding.

Cheers.