关于用NPOI导入Excel

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Linq;
using System.Windows.Forms;
using DevExpress.XtraEditors;
using System.Data.OleDb;
using TenderClear.Common;
using TenderClear.BLL.TC01;
using System.IO;
using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;
using NPOI.SS.Formula.Eval;
using NPOI.XSSF.UserModel;

namespace TenderClear.UI.Forms.TC01
{
    public partial class TC010103Form : DevExpress.XtraEditors.XtraForm
    {
        public TC010103Form()
        {
            InitializeComponent();
        }
        private string xmlx; //项目类型
        private string xmbm;//项目编码
        private string xmmc;//项目名称
        private string xmdw;//项目单位
        private string dydj;//电压等级
        private string zyxf;//专业细分/项目专页
        private DateTime kssj;//开始时间
        private DateTime jssj;//结束时间
        private string xmnr;//项目内容
        private string cjr;//创建人
        private DateTime cjsj;//创建时间
        private void txtExcel_Click(object sender, EventArgs e)
        {
            //打开excel选择框
            OpenFileDialog frm = new OpenFileDialog();
            frm.Filter = "Excel文件(*.xls,xlsx)|*.xls;*.xlsx";
            if (frm.ShowDialog() == DialogResult.OK)
            {
                txtExcel.Text = frm.FileName;
            }
        }

        /// <summary>读取excel
        /// 默认第一行为表头
        /// </summary>
        /// <param name="strFileName">excel文档绝对路径</param>
        /// <param name="rowIndex">内容行偏移量，第一行为表头，内容行从第二行开始则为1</param>
        /// <returns></returns>
        public static DataTable Import(string strFileName, int rowIndex)
        {
            DataTable dt = new DataTable();
            IWorkbook hssfworkbook;
            using (FileStream file = new FileStream(strFileName, FileMode.Open, FileAccess.Read))
            {
                hssfworkbook = WorkbookFactory.Create(file);
            }
            ISheet sheet = hssfworkbook.GetSheetAt(0);


            IRow headRow = sheet.GetRow(0);
            if (headRow != null)
            {
                int colCount = headRow.LastCellNum;
                for (int i = 0; i < colCount; i++)
                {
                    dt.Columns.Add("COL_" + i);
                }
            }


            for (int i = (sheet.FirstRowNum + rowIndex); i <= sheet.LastRowNum; i++)
            {
                IRow row = sheet.GetRow(i);
                bool emptyRow = true;
                object[] itemArray = null;

                if (row != null)
                {
                    itemArray = new object[row.LastCellNum];
                    for (int j = row.FirstCellNum; j < row.LastCellNum; j++)
                    {
                        if (row.GetCell(j) != null)
                        {
                            switch (row.GetCell(j).CellType)
                            {
                                case CellType.Numeric:
                                    if (HSSFDateUtil.IsCellDateFormatted(row.GetCell(j)))//日期

                                    {
                                        itemArray[j] = row.GetCell(j).DateCellValue.ToString("yyyy-MM-dd");
                                    }
                                    else//其他数字类型
                                    {
                                        itemArray[j] = row.GetCell(j).NumericCellValue;
                                    }
                                    break;
                                case CellType.Blank:
                                    itemArray[j] = string.Empty;
                                    break;
                                case CellType.Formula:
                                    if (Path.GetExtension(strFileName).ToLower().Trim() == ".xlsx")
                                    {
                                        XSSFFormulaEvaluator eva = new XSSFFormulaEvaluator(hssfworkbook);
                                        if (eva.Evaluate(row.GetCell(j)).CellType == CellType.Numeric)
                                        {
                                            itemArray[j] = eva.Evaluate(row.GetCell(j)).NumberValue;
                                        }
                                        else
                                        {
                                            itemArray[j] = eva.Evaluate(row.GetCell(j)).StringValue;
                                        }
                                    }
                                    else
                                    {
                                        HSSFFormulaEvaluator eva = new HSSFFormulaEvaluator(hssfworkbook);
                                        if (eva.Evaluate(row.GetCell(j)).CellType == CellType.Numeric)
                                        {
                                            itemArray[j] = eva.Evaluate(row.GetCell(j)).NumberValue;
                                        }
                                        else
                                        {
                                            itemArray[j] = eva.Evaluate(row.GetCell(j)).StringValue;
                                        }
                                    }
                                    break;
                                default:
                                    itemArray[j] = row.GetCell(j).StringCellValue;
                                    break;
                            }

                            if (itemArray[j] != null && !string.IsNullOrEmpty(itemArray[j].ToString().Trim()))
                            {
                                emptyRow = false;
                            }
                        }
                    }
                }

                //非空数据行数据添加到DataTable
                if (!emptyRow)
                {
                    dt.Rows.Add(itemArray);
                }
            }
            return dt;
        }
        private void InsertToDatabase()
        {
            DataTable dt = Import(txtExcel.Text, 1); // 1表示第一行为表头，内容行从第二行开始
            int count = 0;
            foreach (DataRow dr in dt.Rows)
            {
                xmlx = dr[0].ToString();
                xmbm = dr[1].ToString();
                xmmc = dr[2].ToString();
                xmdw = dr[3].ToString();
                dydj = dr[4].ToString();
                zyxf = dr[5].ToString();
                kssj = Convert.ToDateTime(dr[6].ToString());
                jssj = Convert.ToDateTime(dr[7].ToString());
                xmnr = dr[8].ToString();
                count = BLL10101.InsertOrUpdate(xmlx, xmbm, xmmc, xmdw, dydj, zyxf, xmnr, kssj, jssj);
            }
            if (count > 0)
            {
                MsgBox.Sucess("导入成功！");
            }
        }
        private void simpleButton2_Click(object sender, EventArgs e)
        {
            InsertToDatabase();
        }
    }
}