读写Excle,不用office环境

1.下载NPOI.dll,并添加引用

 

2.ExcelHelper帮助类,以下为读写的参照方法

        HSSFWorkbook hssfworkbook;  
        #region  导入Excel 返回Table
        public DataTable ImportExcelFile(string filePath)
        {
            #region//初始化信息
            try
            {
                using (FileStream file = new FileStream(filePath, FileMode.Open, FileAccess.Read))
                {
                    hssfworkbook = new HSSFWorkbook(file);
                }
            }
            catch (Exception e)
            {
                throw e;
            }
            #endregion

            NPOI.SS.UserModel.ISheet sheet = hssfworkbook.GetSheetAt(0);
            System.Collections.IEnumerator rows = sheet.GetRowEnumerator();
            DataTable dt = new DataTable();
            for (int j = 0; j < (sheet.GetRow(0).LastCellNum); j++)
            {
                dt.Columns.Add(Convert.ToChar(((int)'A') + j).ToString());
            }
            while (rows.MoveNext())
            {
                HSSFRow row = (HSSFRow)rows.Current;
                DataRow dr = dt.NewRow();
                for (int i = 0; i < row.LastCellNum; i++)
                {
                    NPOI.SS.UserModel.ICell cell = row.GetCell(i);
                    if (cell == null)
                    {
                        dr[i] = null;
                    }
                    else
                    {
                        dr[i] = cell.ToString();
                    }
                }
                dt.Rows.Add(dr);
            }
            return dt;
        }
        #endregion

        #region 导出excel
        //Datatable导出Excel
        public   MemoryStream  GridToExcelByNPOI(DataTable dt)
        {
            try
            {
                HSSFWorkbook workbook = new HSSFWorkbook();
                ISheet sheet = workbook.CreateSheet("Sheet1");

                ICellStyle HeadercellStyle = workbook.CreateCellStyle();
                HeadercellStyle.BorderBottom = NPOI.SS.UserModel.BorderStyle.Thin;
                HeadercellStyle.BorderLeft = NPOI.SS.UserModel.BorderStyle.Thin;
                HeadercellStyle.BorderRight = NPOI.SS.UserModel.BorderStyle.Thin;
                HeadercellStyle.BorderTop = NPOI.SS.UserModel.BorderStyle.Thin;
                HeadercellStyle.Alignment = NPOI.SS.UserModel.HorizontalAlignment.Center;
                //字体
                NPOI.SS.UserModel.IFont headerfont = workbook.CreateFont();
                headerfont.Boldweight = (short)FontBoldWeight.Bold;
                HeadercellStyle.SetFont(headerfont);


                //用column name 作为列名
                int icolIndex = 0;
                IRow headerRow = sheet.CreateRow(0);
                foreach (DataColumn item in dt.Columns)
                {
                    ICell cell = headerRow.CreateCell(icolIndex);
                    cell.SetCellValue(item.ColumnName);
                    cell.CellStyle = HeadercellStyle;
                    icolIndex++;
                }

                ICellStyle cellStyle = workbook.CreateCellStyle();

                //为避免日期格式被Excel自动替换，所以设定 format 为 『@』 表示一率当成text來看
                cellStyle.DataFormat = HSSFDataFormat.GetBuiltinFormat("@");
                cellStyle.BorderBottom = NPOI.SS.UserModel.BorderStyle.Thin;
                cellStyle.BorderLeft = NPOI.SS.UserModel.BorderStyle.Thin;
                cellStyle.BorderRight = NPOI.SS.UserModel.BorderStyle.Thin;
                cellStyle.BorderTop = NPOI.SS.UserModel.BorderStyle.Thin;


                NPOI.SS.UserModel.IFont cellfont = workbook.CreateFont();
                cellfont.Boldweight = (short)FontBoldWeight.Normal;
                cellStyle.SetFont(cellfont);

                //建立内容行
                int iRowIndex = 1;
                int iCellIndex = 0;
                foreach (DataRow Rowitem in dt.Rows)
                {
                    IRow DataRow = sheet.CreateRow(iRowIndex);
                    foreach (DataColumn Colitem in dt.Columns)
                    {

                        ICell cell = DataRow.CreateCell(iCellIndex);
                        cell.SetCellValue(Rowitem[Colitem].ToString());
                        cell.CellStyle = cellStyle;
                        iCellIndex++;
                    }
                    iCellIndex = 0;
                    iRowIndex++;
                }

                //自适应列宽度
                for (int i = 0; i < icolIndex; i++)
                {
                    sheet.AutoSizeColumn(i);
                }

                //写Excel
                MemoryStream  ms = new MemoryStream ();
                workbook.Write(ms);
                ms.Flush();
                ms.Position = 0;

                return ms;
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }
        #endregion

　　

转载于:https://www.cnblogs.com/sy-ds/p/4422006.html