关于IList集合Remove的问题

Question

private static IList<Employee> employees = new List<Employee>
{
           new Employee{Id = "001" , Name = "张三" , Department = "开发部" , Grade = "G7"},
           new Employee{Id = "002" , Name = "李四" , Department = "人事部" , Grade = "G8"},
};

public Employee Get(string id)
{
          Employee employee = employees.FirstOrDefault<Employee>(p => p.Id.Equals(id));
          return employee;
}

public void Delete(string id)
 {
            Employee employee = this.Get(id);
            if (null != employee)
            {
               if(!employees.Remove(employee))
               {
                   Console.WriteLine("删除失败 :{0}" , employees.Count);
               }
               else
               {
                   Console.WriteLine("删除成功 ：{0}" , employees.Count);
               }
            }
}

这样的问题，我感觉好像出现在linq提供的FirstOrDefault 。 请问 ， 这是什么原因呢 ？ 我今后又该如何有效避免这样的错误呢？

Answer 1

应该是对的，不知道你之前做了何种操作：

namespace ConsoleApplication1
{
    class Employee
    {
        public string Id { get; set; }
        public string Name { get; set; }
        public string Department { get; set; }
    }

    class Program
    {
        private static IList<Employee> employees = new List<Employee>
{
           new Employee{Id = "001" , Name = "张三" , Department = "开发部"},
           new Employee{Id = "002" , Name = "李四" , Department = "人事部"},
};

        public Employee Get(string id)
        {
            Employee employee = employees.FirstOrDefault<Employee>(p => p.Id.Equals(id));
            return employee;
        }
        public void Delete(string id)
        {
            Employee employee = this.Get(id);
            if (null != employee)
            {
                if (!employees.Remove(employee))
                {
                    Console.WriteLine("删除失败 :{0}", employees.Count);
                }
                else
                {
                    Console.WriteLine("删除成功 ：{0}", employees.Count);
                }
            }
        }
        static void Main(string[] args)
        {
            Program p = new Program();
            p.Delete("001");
            Console.WriteLine("成功删除："+employees.Count);
        }
    }
}

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Answer 2

好奇,你能否在Get中输出取到Employee.查看是否存在重复?

Answer 3

具体问题找了，是个人失误照成的。