Question

using System; using System.Collections.Generic; using System.Linq; using System.Linq.Expressions; using System.Text;  namespace ConsoleApplication1 {      public class Class1       {        static void Main(string[] args)        {            List<Car> mylist = new List<Car>();            Car car1;            Car car2;            Car car3;             car1 = new Car()            {                make = 'Honda',                id = 1            };            car2 = new Car()            {                make = 'toyota',                id = 2            };             car3 = new Car()            {               make = 'Honda',               id = 3,               color = 'red'            };             mylist.Add(car1);            mylist.Add(car2);            **////mylist.Where(p => p.id == 1).SingleOrDefault() = car3;**         }             }      public class Car     {         public int id { get; set; }         public string make { get; set; }         public string color { get; set; }      } } 

How can I update the list by replacing the honda car of Id 1 with honda car with Id 3 in the best way.

Answer 1

Everything leppie said – plus:

int index = mylist.FindIndex(p => p.id == 1); if(index<0) {     mylist.Add(car3); } else {     mylist[index] = car3; } 

This just uses the existing FindIndex to locate a car with id 1, then replace or add it. No LINQ; no SQL – just a lambda and List<T>.