/// <summary>
        /// 创建新文件
        /// </summary>
        /// <param name="parentPath">文件路径</param>
        /// <param name="FileName">文件名称</param>
        public void AddFile(string parentPath, string FileName)
        {
            parentPath = Server.MapPath(parentPath);
            bool flag = !Directory.Exists(parentPath + FileName);
            if (!flag)
            {
                HttpContext.Current.Response.Write("<script>alert('该文件以存在');history.go(-1);</script>\uFFFD");
                HttpContext.Current.Response.End();
            }
            else
            {
                Directory.CreateDirectory(parentPath + FileName);
            }
        }
        /// <summary>
        /// 删除文件
        /// </summary>
        /// <param name="fileName">文件路径</param>
        /// <param name="fileType">文件类型</param>
        public void Delete(string fileurl, string fileType)
        {
            bool flag = fileType != "file";//判断文件的类型 file为文件 folder 为文件夹
            if (!flag)
            {//删除文件
                flag = File.Exists(fileurl);
                if (flag)
                {
                    File.Delete(fileurl);
                }
            }
            else
            {//删除文件夹
                flag = Directory.Exists(fileurl);
                if (flag)
                {
                    DirectoryInfo directoryInfo = new DirectoryInfo(fileurl);
                    flag = (directoryInfo.GetDirectories().Length <= 0) && (directoryInfo.GetFiles().Length <= 0);
                    if (!flag)
                    {
                        HttpContext.Current.Response.Write("<script>alert('请先删除文件的子文件');history.go(-1);</script>");
                        HttpContext.Current.Response.End();
                    }
                    else
                    {
                        Directory.Delete(fileurl);
                    }
                }
            }
        }
        /// <summary>
        /// 获得指定文件的文件内容
        /// </summary>
        /// <param name="parentPath">相对路径</param>
        /// <returns></returns>
        public DataSet GetFileList(string parentPath)
        {
            DataRow row;
            string filePath = parentPath;
            DataSet set = new DataSet();
            DataTable table = new DataTable();
            table.Columns.Add("FileType");//指定文件类型 folder 为文件夹
            table.Columns.Add("FileName");//文件名称
            table.Columns.Add("FileIcon");//文件的图标
            table.Columns.Add("FileUrl");//文件的相对路径+文件名称
            table.Columns.Add("FilePath");//文件的相对路径
            table.Columns.Add("FileSize");//文件大小
            table.Columns.Add("FileUrlType");//文件的相对路径+文件名称+类型
            DirectoryInfo info = new DirectoryInfo(HttpContext.Current.Server.MapPath(filePath));
            foreach (DirectoryInfo info2 in info.GetDirectories())
            {//调取文件夹
                row = table.NewRow();
                row["FileType"] = "folder";
                row["FileName"] = info2.Name;
                row["FileIcon"] = "<img src=\"Images/closedfolder.gif\" border=\"0\" />";
                row["FileUrl"] = filePath + "/" + info2.Name;
                row["FilePath"] = filePath;
                row["FileSize"] = "";
                row["FileUrlType"] = filePath + "/" + info2.Name + ";" + "folder";
                table.Rows.Add(row);
            }
            foreach (FileInfo info3 in info.GetFiles())
            {//调取文件
                row = table.NewRow();
                row["FileType"] = "file";
                row["FileName"] = info3.Name;
                row["FileIcon"] = "<img src=\"Images/FileIcon/.gif\" class=\"itemimg\" />";//根据扩展名获得Icon
                row["FileUrl"] = filePath + "/" + info3.Name;
                row["FilePath"] = filePath;
                row["FileSize"] = (info3.Length / 0x3e8L) + "K";
                row["FileUrlType"] = filePath + "/" + info3.Name + ";" + "file";
                table.Rows.Add(row);
            }
            set.Tables.Add(table);
            return set;

        }