将List中部分字段转换为DataTable中

由于原来方法导出数据量比较大 的时候，出现卡顿现象：搜索简单改造：（下面方法借助NPIO）


  /// <summary>
        /// 将List中原文和译文转换为Datatable
        /// </summary>
        /// <typeparam name="MemoryFields">术语</typeparam>
        /// <param name="list">术语列宁表</param>
        /// <returns>只包含原文和译文的DataTable</returns>
        public System.Data.DataTable list2Datatable<MemoryFields>(List<MemoryFields> list)
        {
            PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(typeof(MemoryFields));
            System.Data.DataTable dt = new System.Data.DataTable();
            //for (int i = 0; i < properties.Count; i++)
            //{
            PropertyDescriptor propertyOrig = properties["Orig"];//Orig为字段
            dt.Columns.Add("原文", propertyOrig.PropertyType);
            PropertyDescriptor propertyTran = properties["Tran"]; //Tran为字段
            dt.Columns.Add("译文", propertyTran.PropertyType);

            //}
            object[] values = new object[2];   
            foreach (MemoryFields item in list)
            {
                //for (int i = 0; i < values.Length; i++)
                //{
                values[0] = properties["Orig"].GetValue(item);
                values[1] = properties["Tran"].GetValue(item);
                //}
                dt.Rows.Add(values);
            }
            return dt;
        }

        private string filename = "";
        private IWorkbook workbook = null;
        private FileStream fs = null;
        private bool disposed;
        /// <summary>
        /// 到处到Excel
        /// </summary>
        /// <param name="FileName">导出文件名</param>
        /// <param name="data">table</param>
        /// <param name="sheetName">sheetName</param>
        /// <param name="isColumnWritten"></param>
        /// <returns></returns>
        public int DataTableToExcel(string FileName, System.Data.DataTable data, string sheetName, bool isColumnWritten)
        {
            filename = FileName;
            int i = 0;
            int j = 0;
            int count = 0;
            ISheet sheet = null;

            fs = new FileStream(filename, FileMode.OpenOrCreate, FileAccess.ReadWrite);
            if (filename.IndexOf(".xlsx") > 0) // 2007版本
                workbook = new XSSFWorkbook();
            else if (filename.IndexOf(".xls") > 0) // 2003版本
                workbook = new HSSFWorkbook();
            try
            {
                if (workbook != null)
                {
                    sheet = workbook.CreateSheet(sheetName);
                }
                else
                {
                    return -1;
                }

                if (isColumnWritten == true) //写入DataTable的列名
                {
                    IRow row = sheet.CreateRow(0);
                    for (j = 0; j < data.Columns.Count; ++j)
                    {
                        row.CreateCell(j).SetCellValue(data.Columns[j].ColumnName);
                    }
                    count = 1;
                }
                else
                {
                    count = 0;
                }

                for (i = 0; i < data.Rows.Count; ++i)
                {
                    IRow row = sheet.CreateRow(count);
                    for (j = 0; j < data.Columns.Count; ++j)
                    {
                        row.CreateCell(j).SetCellValue(data.Rows[i][j].ToString());
                    }
                    ++count;
                }
                workbook.Write(fs);  //写入到excel
                return count;
            }
            catch (Exception ex)
            {
                Console.WriteLine("Exception: " + ex.Message);
                return -1;
            }
        }