支持库：FileHelper

    public class FileHelper
    {
        #region 文件名/扩展名/路径名
        /// <summary>
        /// 获取文件名
        /// </summary>
        /// <param name="filepath"></param>
        /// <returns></returns>
        public static string GetFileName(string filepath)
        {
            return File.Exists(filepath) ? new FileInfo(filepath).Name : "";
        }
        /// <summary>
        /// 取文件扩展名
        /// </summary>
        /// <param name="filepath"></param>
        /// <returns></returns>
        public static string GetFileExt(string filepath)
        {
            return File.Exists(filepath) ? new FileInfo(filepath).Extension : "";
        }
        /// <summary>
        /// 取文件所在路径名，结尾不含 “\”
        /// </summary>
        /// <param name="filepath"></param>
        /// <returns></returns>
        public static string GetFolder(string filepath)
        {
            var info = new FileInfo(filepath).Directory;
            return info != null ? info.FullName : "";
        }

        #endregion

        #region 文件读写
        /// <summary>
        /// 读取文本文件内容
        /// </summary>
        /// <param name="filePath">文件路径</param>
        /// <returns></returns>
        public static string ReadTextFile(string filePath)
        {
            string strFileContent = "";
            if (File.Exists(filePath))
            {
                strFileContent = File.ReadAllText(filePath);
            }
            return strFileContent;
        }
        /// <summary>
        /// 文本文件修改/替换
        /// 将文件内容存入filePath指定文件，替换原有内容，若文件不存在，则新建文件
        /// </summary>
        /// <param name="filePath"></param>
        /// <param name="content"> </param>
        /// <returns></returns>
        public static bool ModifyFile(string filePath, string content)
        {
            if (File.Exists(filePath))
            {
                File.Delete(filePath);
            }
            using (FileStream fs = File.Create(filePath))
            {
                Byte[] file = new UTF8Encoding(true).GetBytes(content);
                fs.Write(file, 0, file.Length);
            }
            return File.Exists(filePath);
        }
        /// <summary>
        /// 二进制文件修改/替换
        /// 将文件内容存入filePath指定文件，替换原有内容，若文件不存在，则新建文件
        /// </summary>
        /// <param name="filepath"></param>
        /// <param name="file"></param>
        /// <returns></returns>
        public static bool ModifyFile(string filepath, byte[] file)
        {
            if (File.Exists(filepath))
            {
                File.Delete(filepath);
            }
            using (FileStream fs = File.Create(filepath))
            {
                fs.Write(file, 0, file.Length);
            }
            return File.Exists(filepath);
        }
        /// <summary>
        /// 文本文件附加
        /// 将内容附加到文件尾
        /// </summary>
        /// <param name="filepath"></param>
        /// <param name="content"></param>
        public static void AppendFile(string filepath, string content)
        {
            if (!File.Exists(filepath))
            {
                ModifyFile(filepath, content);
            }
            else
            {
                using (var fs = File.AppendText(filepath))
                {
                    fs.WriteLine(content);
                }
            }
        }

        #endregion


    }