c# 对文件操作

/// <summary>
        /// 获得当前绝对路径
        /// </summary>
        /// <param name="strPath">指定的路径</param>
        /// <returns>绝对路径</returns>
        public static string GetMapPath(string strPath)
        {
            if (strPath.ToLower().StartsWith("http://"))
            {
                return strPath;
            }
            if (HttpContext.Current != null)
            {
                return HttpContext.Current.Server.MapPath(strPath);
            }
            else //非web程序引用
            {
                strPath = strPath.Replace("/", "\");
                if (strPath.StartsWith("\"))
                {
                    strPath = strPath.Substring(strPath.IndexOf('\', 1)).TrimStart('\');
                }
                return System.IO.Path.Combine(AppDomain.CurrentDomain.BaseDirectory, strPath);
            }
        }

        /// <summary>
        /// 删除单个文件
        /// </summary>
        /// <param name="_filepath">文件相对路径</param>
        public static bool DeleteFile(string _filepath)
        {
            if (string.IsNullOrEmpty(_filepath))
            {
                return false;
            }
            string fullpath = GetMapPath(_filepath);
            if (File.Exists(fullpath))
            {
                File.Delete(fullpath);
                return true;
            }
            return false;
        }

        /// <summary>
        /// 删除上传的文件(及缩略图)
        /// </summary>
        /// <param name="_filepath"></param>
        public static void DeleteUpFile(string _filepath)
        {
            if (string.IsNullOrEmpty(_filepath))
            {
                return;
            }
            string fullpath = GetMapPath(_filepath); //原图
            if (File.Exists(fullpath))
            {
                File.Delete(fullpath);
            }
            if (_filepath.LastIndexOf("/") >= 0)
            {
                string thumbnailpath = _filepath.Substring(0, _filepath.LastIndexOf("/")) + "mall_" + _filepath.Substring(_filepath.LastIndexOf("/") + 1);
                string fullTPATH = GetMapPath(thumbnailpath); //宿略图
                if (File.Exists(fullTPATH))
                {
                    File.Delete(fullTPATH);
                }
            }
        }

        /// <summary>
        /// 删除指定文件夹
        /// </summary>
        /// <param name="_dirpath">文件相对路径</param>
        public static bool DeleteDirectory(string _dirpath)
        {
            if (string.IsNullOrEmpty(_dirpath))
            {
                return false;
            }
            string fullpath = GetMapPath(_dirpath);
            if (Directory.Exists(fullpath))
            {
                Directory.Delete(fullpath, true);
                return true;
            }
            return false;
        }

        /// <summary>
        /// 修改指定文件夹名称
        /// </summary>
        /// <param name="old_dirpath">旧相对路径</param>
        /// <param name="new_dirpath">新相对路径</param>
        /// <returns>bool</returns>
        public static bool MoveDirectory(string old_dirpath, string new_dirpath)
        {
            if (string.IsNullOrEmpty(old_dirpath))
            {
                return false;
            }
            string fulloldpath = GetMapPath(old_dirpath);
            string fullnewpath = GetMapPath(new_dirpath);
            if (Directory.Exists(fulloldpath))
            {
                Directory.Move(fulloldpath, fullnewpath);
                return true;
            }
            return false;
        }

        /// <summary>
        /// 返回文件大小KB
        /// </summary>
        /// <param name="_filepath">文件相对路径</param>
        /// <returns>int</returns>
        public static int GetFileSize(string _filepath)
        {
            if (string.IsNullOrEmpty(_filepath))
            {
                return 0;
            }
            string fullpath = GetMapPath(_filepath);
            if (File.Exists(fullpath))
            {
                FileInfo fileInfo = new FileInfo(fullpath);
                return ((int)fileInfo.Length) / 1024;
            }
            return 0;
        }

        /// <summary>
        /// 返回文件扩展名，不含“.”
        /// </summary>
        /// <param name="_filepath">文件全名称</param>
        /// <returns>string</returns>
        public static string GetFileExt(string _filepath)
        {
            if (string.IsNullOrEmpty(_filepath))
            {
                return "";
            }
            if (_filepath.LastIndexOf(".") > 0)
            {
                return _filepath.Substring(_filepath.LastIndexOf(".") + 1); //文件扩展名，不含“.”
            }
            return "";
        }

        /// <summary>
        /// 返回文件名，不含路径
        /// </summary>
        /// <param name="_filepath">文件相对路径</param>
        /// <returns>string</returns>
        public static string GetFileName(string _filepath)
        {
            return _filepath.Substring(_filepath.LastIndexOf(@"/") + 1);
        }

        /// <summary>
        /// 文件是否存在
        /// </summary>
        /// <param name="_filepath">文件相对路径</param>
        /// <returns>bool</returns>
        public static bool FileExists(string _filepath)
        {
            string fullpath = GetMapPath(_filepath);
            if (File.Exists(fullpath))
            {
                return true;
            }
            return false;
        }