将list输出成Excel到指定目录

            System.Data.DataTable dtSource = ToDataTable<EmpExtension>(empList);  //数据源

            context.Response.ContentType = "application/vnd.ms-excel";
            context.Response.ContentEncoding = Encoding.UTF8;
            context.Response.Charset = "UTF-8";
            context.Response.AppendHeader("Content-Disposition",
                "attachment;filename=" + HttpUtility.UrlEncode(strFileName, Encoding.UTF8));  //路径：HttpUtility.UrlEncode(strFileName, Encoding.UTF8)


            HSSFWorkbook workbook = new HSSFWorkbook();
            HSSFSheet sheet = (HSSFSheet)workbook.CreateSheet();

            //填充表头
            HSSFRow dataRow = (HSSFRow)sheet.CreateRow(0);
            foreach (DataColumn column in dtSource.Columns)
            {
                dataRow.CreateCell(column.Ordinal).SetCellValue(column.ColumnName);
            }


            //填充内容
            for (int i = 0; i < dtSource.Rows.Count; i++)
            {
                dataRow = (HSSFRow)sheet.CreateRow(i + 1);
                for (int j = 0; j < dtSource.Columns.Count; j++)
                {
                    dataRow.CreateCell(j).SetCellValue(dtSource.Rows[i][j].ToString());
                }
            }

            using (MemoryStream ms = new MemoryStream())
            {
                using (FileStream fs = new FileStream(strFileName, FileMode.Create, FileAccess.Write))
                {
                    workbook.Write(fs);
                }
                ms.Flush();

                context.Response.BinaryWrite(ms.GetBuffer());
            }

这里使用了NPOI，还有context可以使用HttpContext.Current代替。strFileName是自定义的路径

另外，将list转化成DataTable的方法：

public static DataTable ToDataTable<T>(List<T> items)
        {
            DataTable dataTable = new DataTable();

            PropertyInfo[] Props = typeof(T).GetProperties(BindingFlags.Public | BindingFlags.Instance);
            foreach (PropertyInfo prop in Props)
            {
                dataTable.Columns.Add(prop.Name);
            }

            foreach (T obj in items)
            {
                var values = new object[Props.Length];
                for (int i = 0; i < Props.Length; i++)
                {
                    values[i] = Props[i].GetValue(obj, null);
                }
                dataTable.Rows.Add(values);
            }

            return dataTable;
        }