C# winform 记住密码实现代码

 using System;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Data;
 using System.Drawing;
 using System.Text;
 using System.Windows.Forms;

 namespace Remember
 {
     public partial class Form1 : Form
     {
         public Form1()
         {
             InitializeComponent();
         }
         //登录
         private void btn_Login_Click(object sender, EventArgs e)
         {
             //记住密码
             if (cb_remember.Checked == true)
             {
                 WriteIni("My Section", this.tb_UserName.Text.ToString(), this.tb_Password.Text.ToString(),
                     string.Format(@"{0}\xtflz.dll", Application.StartupPath));
                 MessageBox.Show("写入成功");
             }
             else
             {
                 WriteIni("My Section", this.tb_UserName.Text.ToString(),"",
                         string.Format(@"{0}\xtflz.dll", Application.StartupPath));
             }
         }
         #region 登录记住密码
         /// <summary>
         /// 提供INI文件的写操作(如Key和Value都为空(null), 则删除Section指定的节下所有键值(包括节名)[如Value为空(null), 则删除Section节下Key键值])
         /// </summary>
         /// <param name="Section">指定的节名</param>
         /// <param name="Key">指定的键名</param>
         /// <param name="Value">Key的值(请将相应的类型ing,long...转换为string类型)</param>
         /// <param name="FilePath">INI文件全路径</param>
         /// <returns></returns>
         public static bool WriteIni(string Section, string Key, string Value, string FilePath)
         {
             //成功返回非零
             long lRe = WritePrivateProfileString(Section, Key, Value, FilePath);
             return lRe == 0L ? false : true;
         }
         /// <summary>
         /// 提供INI文件的读操作
         /// </summary>
         /// <param name="Section">指定的节名</param>
         /// <param name="Key">指定的键名</param>
         /// <param name="FilePath">INI文件全路径</param>
         /// <returns>请将string类型转换为相应int,long的类型(返回值不应超过255字符)</returns>
         public static string ReadIni(string Section, string Key, string FilePath)
         {
             int Size = ;
             StringBuilder ReStr = new StringBuilder();
             GetPrivateProfileString(Section, Key, "ERROR...", ReStr, Size, FilePath);
             if (ReStr.ToString() == "ERROR...")
             {
                 return null;
             }
             return ReStr.ToString();
         }
         /// <summary>
         /// C＃申明INI文件的写操作函数WritePrivateProfileString（）
         /// </summary>
         /// <param name="Section"></param>
         /// <param name="Key"></param>
         /// <param name="Value"></param>
         /// <param name="FilePath"></param>
         /// <returns></returns>
         //读写INI文件功能
         [System.Runtime.InteropServices.DllImport("kernel32")]
         public static extern long WritePrivateProfileString(string Section,
             //指定的节名
             string Key,
             //指定的键名
             string Value,
             string FilePath);
         /// <summary>
         /// C＃申明INI文件的读操作函数GetPrivateProfileString
         /// </summary>
         /// <param name="Section"></param>
         /// <param name="key"></param>
         /// <param name="Def"></param>
         /// <param name="RetVal"></param>
         /// <param name="Size"></param>
         /// <param name="FilePath"></param>
         /// <returns></returns>
         [System.Runtime.InteropServices.DllImport("kernel32")]
         public static extern int GetPrivateProfileString(string Section,
             //指定的节名
             string key,
             //指定的键名
             string Def,
             //如果未取得正确的值则返回自定义的字符串
             StringBuilder RetVal,
             //保存字符串值
             int Size,
             //指定RetVal的长度
             string FilePath);
         //ini文件路径(如果ini文件不在操作系统文件夹内,则必须指定ini文件的绝对路径)
         #endregion 登录记住密码
         private void tb_UserName_TextChanged(object sender, EventArgs e)
         {
             string s = this.tb_UserName.Text.ToString();
             string result = ReadIni("My Section",s,string.Format(@"{0}\xtflz.dll",Application.StartupPath));
             if (result == null || result == "")
             {
                 this.tb_Password.Text = "";
                 this.cb_remember.Checked = false;
             }
             else
             {
                 this.tb_Password.Text = result;
                 this.cb_remember.Checked = true;
             }
         }
     }
 }