using System;

 using System.Collections.Generic;

 using System.ComponentModel;

 using System.Data;

 using System.Drawing;

 using System.Linq;

 using System.Text;

 using System.Windows.Forms;

 using System.Collections;

 using System.IO;

 using System.Runtime.Serialization.Formatters.Binary;

 namespace xtragrid

 {

     public partial class Form1 : Form

     {

         ArrayList al = new ArrayList(); //用此存储用户名 当然还想存储密码就用Dictionary<>

         public Form1()

         {

             InitializeComponent();

         }

          //窗体load 读取本地user.data文件，获取用户

         private void Form1_Load(object sender, EventArgs e)

         {

             FileStream fs = new FileStream("user.data",FileMode.OpenOrCreate);//打开user.data，若不存在就建立新的

             if (fs.Length>)

             {

                 BinaryFormatter bf = new BinaryFormatter();

                 al = bf.Deserialize(fs) as ArrayList; //将打开的文件流反序列化到al

                 foreach (string item in al)

                 {

                     this.comboBox1.Items.Add(item); //将al各项添加到combobox中

                 }

             }

             fs.Close();  //关闭流

             this.comboBox1.SelectedIndex = this.comboBox1.Items.Count - ; //设置combobox默认项

         }

         //登陆按钮

         private void button1_Click(object sender, EventArgs e)

         {

             string name = this.comboBox1.Text;

             //check name

             if (true) //存在此用户

             {

                 if (this.checkBox1.Checked)  //勾选记住用户

                 {

                     if (!al.Contains(name)) //如果al中没有这个用户

                     {

                         FileStream fs = new FileStream("user.data", FileMode.Create); //创建新文件user.data

                         BinaryFormatter bf = new BinaryFormatter(); //创建二进制序列化对象

                         al.Add(name);

                         bf.Serialize(fs, al); //序列化到fs

                         fs.Close();           //关闭文件流

                     }

                 }

                 //login code

             }

             else

             {

                 //no user

             } 

         }

     }

 }