C# NPOI导出Excel 表格宽度自适应，支持中文

 /// <summary>
        /// 转换内存表为Office2007版本以上的EXCEL文件流
        /// </summary>
        /// <param name="sourceTable"></param>
        /// <param name="sheetName"></param>
        /// <param name="dateTimeFormat"></param>
        /// <returns></returns>
        public static MemoryStream DataTableToXLSXStream(DataTable sourceTable, string sheetName = "Sheet1", string dateTimeFormat = "yyyy-MM-dd HH:mm:ss")
        {
            XSSFWorkbook workbook = new XSSFWorkbook();
            WriteReportToXLSXSheet(workbook, sourceTable, sheetName, dateTimeFormat);
            ISheet sheet = workbook.GetSheetAt(0);
            //设置自适应宽度,9为Excel列数，根据需要自已修改
            for (int columnNum = 0; columnNum <= 9; columnNum++)
            {
                int columnWidth = sheet.GetColumnWidth(columnNum) / 256;
                //5为开始修改的行数，默认为0行开始
                for (int rowNum = 5; rowNum <= sheet.LastRowNum; rowNum++)
                {
                    IRow currentRow = sheet.GetRow(rowNum);
                    if (currentRow.GetCell(columnNum) != null)
                    {
                        ICell currentCell = currentRow.GetCell(columnNum);
                        int length = Encoding.Default.GetBytes(currentCell.ToString()).Length+1;
                        if (columnWidth < length)
                        {
                            columnWidth = length;
                        }
                    }
                }
                sheet.SetColumnWidth(columnNum, columnWidth * 256);
            }
            MemoryStream ms = new MemoryStream();
            workbook.Write(ms, true);
            ms.Seek(0, SeekOrigin.Begin);
            return ms;
        }