读写Excle,不用office环境

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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