list.ForEach AsReadOnly

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Diagnostics;

namespace ConsoleApplication7
{
    class Program
    {
        static void Main(string[] args)
        {
            List<Per> list = new List<Per>();
            list.Add(new Per(1));
            list.Add(new Per(2));
            list.Add(new Per(3));

            var ReadOnlyList = list.AsReadOnly(); //  集合只读

            list.ForEach(x => Console.WriteLine(x.Id));  //  遍历
            Console.ReadKey();

        }
    }




    class Per
    {


        public Per(int id)
        {
            this.Id = id;
        }

        public int Id { get; set; }


    }
}