实现类似QQ记住密码的功能

记住用户的密码，一般浏览器都有这个功能，基于C/S结构的软件实现这个功能也有很多方法，这里采用简单的文件流保存用户名及密码的方法来实现这个功能。

Person类，模拟用户

using LMSys.Model;using System;using System.Collections.Generic;using System.IO;using System.Linq;using System.Runtime.Serialization.Formatters.Binary;using System.Text;using System.Threading.Tasks;namespace LMSys.BLL{    public class RememberUser    {        private static Dictionary<string, Person> persons = new Dictionary<string, Person>();        /// <summary>        /// 构造函数，读取文件流        /// </summary>        public RememberUser()        {            FileStream fs = new FileStream("Data.bin", FileMode.OpenOrCreate);            if (fs.Length > 0)            {                BinaryFormatter bf = new BinaryFormatter();                persons = bf.Deserialize(fs) as Dictionary<string, Person>;            }            fs.Close();        }        /// <summary>        /// 返回保存的用户列表        /// </summary>        /// <returns></returns>        public Dictionary<string, Person> GetList()        {            return persons;        }        /// <summary>        /// 添加新用户        /// </summary>        /// <param name="person"></param>        public void AddRemember(Person person)        {            FileStream fs = new FileStream("Data.bin", FileMode.Create);            BinaryFormatter bf = new BinaryFormatter();            if (persons.ContainsKey(person.UserName))//若已存在用户，先移除该用户            {                persons.Remove(person.UserName);            }            persons.Add(person.UserName, person);//再添加该用户，防止用户密码更新            bf.Serialize(fs, persons);            fs.Close();        }    }}