using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;

namespace HandleINI
{
    class Program
    {
        static void Main(string[] args)
        {
            string filePath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Config.ini");//在当前程序路径创建

            #region 创建INI文件
            FileStream INIFile = File.Create(filePath);
            INIFile.Close();
            #endregion


            //写入节点1
            INIHelper.Write("s1", "1", "a", filePath);
            INIHelper.Write("s1", "2", "b", filePath);
            INIHelper.Write("s1", "3", "c", filePath);


            //写入节点2
            INIHelper.Write("s2", "4", "d", filePath);
            INIHelper.Write("s2", "5", "e", filePath);

            //改节点value值（就是重写一遍）
            INIHelper.Write("s1", "3", "c3", filePath);

            //读取节点1中的key为1的值
            string value = INIHelper.Read("s1", "1", "", filePath);
            Console.WriteLine(value);

            INIHelper.DeleteKey("s1", "2", filePath);//删除节点s1中key为2的值
            INIHelper.DeleteSection("s2", filePath);//删除节点s2
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;
using System.IO;

namespace HandleINI
{
    /// <summary>
    /// INI文件操作类
    /// </summary>
    public class INIHelper
    {
        /// <summary>
        /// 为INI文件中指定的节点取得字符串
        /// </summary>
        /// <param name="lpAppName">欲在其中查找关键字的节点名称</param>
        /// <param name="lpKeyName">欲获取的项名</param>
        /// <param name="lpDefault">指定的项没有找到时返回的默认值</param>
        /// <param name="lpReturnedString">指定一个字串缓冲区，长度至少为nSize</param>
        /// <param name="nSize">指定装载到lpReturnedString缓冲区的最大字符数量</param>
        /// <param name="lpFileName">INI文件完整路径</param>
        /// <returns>复制到lpReturnedString缓冲区的字节数量，其中不包括那些NULL中止字符</returns>
        [DllImport("kernel32")]
        private static extern int GetPrivateProfileString(string lpAppName, string lpKeyName, string lpDefault, StringBuilder lpReturnedString, int nSize, string lpFileName);

        /// <summary>
        /// 修改INI文件中内容
        /// </summary>
        /// <param name="lpApplicationName">欲在其中写入的节点名称</param>
        /// <param name="lpKeyName">欲设置的项名</param>
        /// <param name="lpString">要写入的新字符串</param>
        /// <param name="lpFileName">INI文件完整路径</param>
        /// <returns>非零表示成功，零表示失败</returns>
        [DllImport("kernel32")]
        private static extern int WritePrivateProfileString(string lpApplicationName, string lpKeyName, string lpString, string lpFileName);

        /// <summary>
        /// 读取INI文件值
        /// </summary>
        /// <param name="section">节点名</param>
        /// <param name="key">键</param>
        /// <param name="def">未取到值时返回的默认值</param>
        /// <param name="filePath">INI文件完整路径</param>
        /// <returns>读取的值</returns>
        public static string Read(string section, string key, string def, string filePath)
        {
            StringBuilder sb = new StringBuilder(1024);
            GetPrivateProfileString(section, key, def, sb, 1024, filePath);
            return sb.ToString();
        }

        /// <summary>
        /// 写INI文件值
        /// </summary>
        /// <param name="section">欲在其中写入的节点名称</param>
        /// <param name="key">欲设置的项名</param>
        /// <param name="value">要写入的新字符串</param>
        /// <param name="filePath">INI文件完整路径</param>
        /// <returns>非零表示成功，零表示失败</returns>
        public static int Write(string section, string key, string value, string filePath)
        {
            CheckPath(filePath);
            return WritePrivateProfileString(section, key, value, filePath);
        }

        /// <summary>
        /// 删除节
        /// </summary>
        /// <param name="section">节点名</param>
        /// <param name="filePath">INI文件完整路径</param>
        /// <returns>非零表示成功，零表示失败</returns>
        public static int DeleteSection(string section, string filePath)
        {
            return Write(section, null, null, filePath);
        }

        /// <summary>
        /// 删除键的值
        /// </summary>
        /// <param name="section">节点名</param>
        /// <param name="key">键名</param>
        /// <param name="filePath">INI文件完整路径</param>
        /// <returns>非零表示成功，零表示失败</returns>
        public static int DeleteKey(string section, string key, string filePath)
        {
            return Write(section, key, null, filePath);
        }

        /// <summary>
        /// 检查文件是否存在
        /// </summary>
        /// <param name="filePath"></param>
        /// <returns></returns>
        private static void CheckPath(string filePath)
        {
            if (string.IsNullOrWhiteSpace(filePath) || !File.Exists(filePath))
            {
                throw new ArgumentNullException("filePath");
            }
        }
    }
}