using System;

using System.Collections.Generic;

using System.Linq;

public class Part : IEquatable<Part>

    {

        public string PartName { get; set; }

​

        public int PartId { get; set; }

​

        public override string ToString()

        {

            return "ID: " + PartId + "   Name: " + PartName;

        }

        public override bool Equals(object obj)

        {

            if (obj == null) return false;

            Part objAsPart = obj as Part;

            if (objAsPart == null) return false;

            else return Equals(objAsPart);

        }

        public override int GetHashCode()

        {

            return PartId;

        }

        public bool Equals(Part other)

        {

            if (other == null) return false;

            return (this.PartId.Equals(other.PartId));

        }

    // Should also override == and != operators.

    }

​

public class Program

{

    public static void Main()

    {

        List<Part> parts = new List<Part>();

​

        // Add parts to the list.

        parts.Add(new Part() {PartName="crank arm", PartId=1234});

        parts.Add(new Part() { PartName = "chain ring", PartId = 1334 });

        parts.Add(new Part() { PartName = "regular seat", PartId = 1434 });

        parts.Add(new Part() { PartName = "banana seat", PartId = 1444 });

        parts.Add(new Part() { PartName = "cassette", PartId = 1534 });

        parts.Add(new Part() { PartName = "chain ring", PartId = 1634 });

​

        Console.WriteLine(parts.FirstOrDefault(x => x.PartName == "chain ring4" ));

    }

}