class Program
    {
        static IsolationLevel currentIsolationLevel = IsolationLevel.ReadCommitted;

        static void Main(string[] args)
        {
            Task.Run(() =>
            {
                Console.WriteLine("Start 1");
                DoInTransaction((context) =>
                {
                    var user1 = context.Users.AsNoTracking().First();
                    Console.WriteLine("sleep 1...");
                    Thread.Sleep(3000);
                    user1.Name = "1";
                    context.Entry(user1).State = System.Data.Entity.EntityState.Modified;
                    Console.WriteLine("try save 1");
                    context.SaveChanges();
                });
                Console.WriteLine("End 1");
            });


            Task.Run(() =>
            {
                Console.WriteLine("Start 2");
                DoInTransaction((context) =>
                {
                    var user1 = context.Users.AsNoTracking().First();
                    Console.WriteLine("sleep 2...");
                    Thread.Sleep(3000);
                    user1.Name = "2";
                    context.Entry(user1).State = System.Data.Entity.EntityState.Modified;
                    Console.WriteLine("try save 2");
                    context.SaveChanges();
                });
                Console.WriteLine("End 2");
            });


            Console.ReadKey();

        }

        private static void DoInTransaction(Action<EFContext> action)
        {
            using (var context = new EFContext())
            {
                using (var transaction = context.Database.BeginTransaction(currentIsolationLevel))
                {
                    try
                    {
                        action(context);
                        transaction.Commit();
                    }
                    catch (Exception ex)
                    {
                        try
                        {
                            transaction.Rollback();
                        }
                        catch
                        {
                            ;// PrintException(ext);
                        }
                        PrintException(ex);
                    }
                }
            }
        }

        private static void PrintException(Exception ex)
        {
            Console.WriteLine(ex.Message);
            if (ex.InnerException != null)
                PrintException(ex.InnerException);
        }
    }