excel导入导出

 public class Excel
    {



        /// <summary>  
        /// 将excel导入到datatable  
        /// </summary>  
        /// <param name="filePath">excel路径</param>  
        /// <param name="isColumnName">第一行是否是列名</param>  
        /// <returns>返回datatable</returns>  
        public static DataTable ExcelToDataTable(string filePath, bool isColumnName, int type = 0, int whethertitle = 0)
        {
            DataTable dataTable = null;
            FileStream fs = null;
            DataColumn column = null;
            DataRow dataRow = null;
            IWorkbook workbook = null;
            ISheet sheet = null;
            IRow row = null;
            ICell cell = null;
            int startRow = 0;
            try
            {
                #region
                if (type == 0)
                {
                    using (fs = File.OpenRead(filePath))
                    {
                        // 2007版本  
                        if (filePath.IndexOf(".xlsx") > 0)
                            workbook = new XSSFWorkbook(fs);
                        // 2003版本  
                        else if (filePath.IndexOf(".xls") > 0)
                            workbook = new HSSFWorkbook(fs);

                        if (workbook != null)
                        {
                            sheet = workbook.GetSheetAt(0);//读取第一个sheet，当然也可以循环读取每个sheet  
                            dataTable = new DataTable();
                            if (sheet != null)
                            {
                                int rowCount = sheet.LastRowNum;//总行数  
                                if (rowCount > 0)
                                {
                                    IRow firstRow = sheet.GetRow(0);//第一行  
                                    if (whethertitle > 0)
                                        firstRow = sheet.GetRow(1);//第二行 
                                    int cellCount = firstRow.LastCellNum;//列数  

                                    //构建datatable的列  
                                    if (isColumnName)
                                    {
                                        startRow = 1;//如果第一行是列名，则从第二行开始读取  
                                        for (int i = firstRow.FirstCellNum; i < cellCount; ++i)
                                        {
                                            cell = firstRow.GetCell(i);
                                            cell.SetCellType(CellType.String);
                                            if (cell != null)
                                            {
                                                if (cell.StringCellValue != null)
                                                {
                                                    column = new DataColumn(cell.StringCellValue);
                                                    dataTable.Columns.Add(column);
                                                }
                                            }
                                        }
                                    }
                                    else
                                    {
                                        for (int i = firstRow.FirstCellNum; i < cellCount; ++i)
                                        {
                                            column = new DataColumn("column" + (i + 1));
                                            dataTable.Columns.Add(column);
                                        }
                                    }
                                    if (whethertitle > 0)
                                        startRow = 2;
                                    //填充行  
                                    for (int i = startRow; i <= rowCount; ++i)
                                    {
                                        row = sheet.GetRow(i);
                                        if (row == null) continue;

                                        dataRow = dataTable.NewRow();
                                        bool flag = false;
                                        if (row.FirstCellNum >= 0)
                                        {
                                            for (int j = row.FirstCellNum; j < cellCount; ++j)
                                            {
                                                cell = row.GetCell(j);
                                                if (cell == null)
                                                    dataRow[j] = "";
                                                else
                                                {
                                                    switch (cell.CellType)
                                                    {
                                                        case CellType.Blank:
                                                            dataRow[j] = "";
                                                            break;
                                                        case CellType.Numeric:
                                                            short format = cell.CellStyle.DataFormat;
                                                            //对时间格式（2015.12.5、2015/12/5、2015-12-5等）的处理  
                                                            if (format == 14 || format == 31 || format == 57 || format == 58)
                                                                dataRow[j] = cell.DateCellValue;
                                                            else
                                                                dataRow[j] = cell.NumericCellValue;
                                                            flag = true;
                                                            break;
                                                        case CellType.String:
                                                            dataRow[j] = cell.StringCellValue;
                                                            flag = true;
                                                            break;
                                                        default:
                                                            dataRow[j] = row.GetCell(j).StringCellValue;
                                                            break;
                                                    }
                                                }
                                            }
                                        }
                                        if (flag)
                                            dataTable.Rows.Add(dataRow);
                                    }
                                }
                            }
                        }
                    }
                }
                #endregion

                #region
                else
                {
                    using (fs = File.OpenRead(filePath))
                    {
                        // 2007版本  
                        if (filePath.IndexOf(".xlsx") > 0)
                            workbook = new XSSFWorkbook(fs);
                        // 2003版本  
                        else if (filePath.IndexOf(".xls") > 0)
                            workbook = new HSSFWorkbook(fs);

                        if (workbook != null)
                        {
                            sheet = workbook.GetSheetAt(0);//读取第一个sheet，当然也可以循环读取每个sheet  
                            dataTable = new DataTable();
                            if (sheet != null)
                            {
                                int rowCount = sheet.LastRowNum;//总行数  
                                if (rowCount > 0)
                                {
                                    IRow firstRow = sheet.GetRow(1);//第一行  
                                    if (whethertitle > 0)
                                        firstRow = sheet.GetRow(1);//第二行
                                    int cellCount = firstRow.LastCellNum;//列数  

                                    //构建datatable的列  
                                    if (isColumnName)
                                    {
                                        startRow = 1;//如果第一行是列名，则从第二行开始读取  
                                        for (int i = firstRow.FirstCellNum; i < cellCount; ++i)
                                        {
                                            cell = firstRow.GetCell(i);
                                            if (cell != null)
                                            {
                                                if (cell.StringCellValue != null)
                                                {
                                                    column = new DataColumn(cell.StringCellValue);
                                                    dataTable.Columns.Add(column);
                                                }
                                            }
                                        }
                                    }
                                    else
                                    {
                                        for (int i = firstRow.FirstCellNum; i < cellCount; ++i)
                                        {
                                            column = new DataColumn("column" + (i + 1));
                                            dataTable.Columns.Add(column);
                                        }
                                    }
                                    startRow = 2;
                                    if (whethertitle > 0)
                                        startRow = 3;
                                    //填充行  
                                    for (int i = startRow; i <= rowCount; ++i)
                                    {
                                        row = sheet.GetRow(i);
                                        if (row == null) continue;
                                        bool flag = false;
                                        dataRow = dataTable.NewRow();
                                        for (int j = row.FirstCellNum; j < cellCount; ++j)
                                        {
                                            cell = row.GetCell(j);
                                            if (cell == null)
                                                dataRow[j] = "";
                                            else
                                            {
                                                //CellType(Unknown = -1,Numeric = 0,String = 1,Formula = 2,Blank = 3,Boolean = 4,Error = 5,)  
                                                switch (cell.CellType)
                                                {
                                                    case CellType.Blank:
                                                        dataRow[j] = "";
                                                        break;
                                                    case CellType.Numeric:
                                                        short format = cell.CellStyle.DataFormat;
                                                        //对时间格式（2015.12.5、2015/12/5、2015-12-5等）的处理  
                                                        if (format == 14 || format == 31 || format == 57 || format == 58)
                                                            dataRow[j] = cell.DateCellValue;
                                                        else
                                                            dataRow[j] = cell.NumericCellValue;
                                                        flag = true;
                                                        break;
                                                    case CellType.String:
                                                        dataRow[j] = cell.StringCellValue;
                                                        flag = true;
                                                        break;
                                                }
                                            }
                                        }
                                        if (flag)
                                            dataTable.Rows.Add(dataRow);
                                    }
                                }
                            }
                        }
                    }

                }
                #endregion

                return dataTable;
            }
            catch (Exception ex)
            {
                if (fs != null)
                {
                    fs.Close();
                }
                return null;
            }
        }

        private string fileName = null; //文件名
        private IWorkbook workbook = null;
        private FileStream fs = null;
        private bool disposed;
        public Excel(string filenames)
        {
            this.fileName = filenames;
            disposed = false;
        }


        /// <summary>
        /// 将datatable导入到excel
        /// </summary>
        /// <param name="dt">DataTable查询数据</param>
        /// <param name="sheetName">表名</param>
        /// <param name="isColumnName">是否添加表名</param>
        /// <returns></returns>
        public int DataTableToExcel(DataTable dt, string sheetName, bool isColumnName)
        {
           // NPOI.HSSF.UserModel.HSSFWorkbook workbook = new HSSFWorkbook();
            fs = new FileStream(fileName, FileMode.OpenOrCreate, FileAccess.ReadWrite);
            int count = 0; //行数
            ISheet sheet = null;


            /*=========判断Excel版本===========*/
            if (fileName.IndexOf(".xlsx") > 0)
            {
                workbook = new XSSFWorkbook();
            }
            else
            {
                workbook = new HSSFWorkbook();
            }



            try
            {
                if (workbook != null)
                {
                    //创建表并赋予Excel表名
                    sheet = workbook.CreateSheet(sheetName);
                }
                else
                {
                    return -1;
                }
                if (isColumnName == true) //true 添加列名 false 不添加
                {
                    //创建第一行
                    IRow row = sheet.CreateRow(0);

                    //循环填充第一行
                    for (int i = 0; i < dt.Columns.Count; ++i)
                    {
                        row.CreateCell(i).SetCellValue(dt.Columns[i].ColumnName);
                    }
                    count = 1;
                }

                //填充除去第一行的数据
                for (int i = 0; i < dt.Rows.Count; ++i)
                {
                    //创建一行
                    IRow row = sheet.CreateRow(count);

                    //填充创建的行的列的数据
                    for (int j = 0; j < dt.Columns.Count; ++j)
                    {
                        row.CreateCell(j).SetCellValue(dt.Rows[i][j].ToString());
                    }

                    count++;
                }

              
                workbook.Write(fs);


                workbook.Close();
                return count;


            }
            catch (Exception ex)
            {

                return -1;
            }




        }






        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        protected virtual void Dispose(bool disposing)
        {
            if (!this.disposed)
            {
                if (disposing)
                {
                    if (fs != null)
                        fs.Close();
                }

                fs = null;
                disposed = true;
            }
        }

    }