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 = 255;
            StringBuilder ReStr = new StringBuilder(255);
            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;
            }
        }
    }
}