winform登陆 记住用户名 代码

 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
             } 

         }
     }
 }