private void button1_Click(object sender, EventArgs e)//选取文件
        {
            OpenFileDialog openFileDialog1 = new OpenFileDialog();
            if (openFileDialog1.ShowDialog() == DialogResult.OK)
            {
                if (openFileDialog1.FileName != "")
                {
                    this.textBox1.Text = openFileDialog1.FileName;
                }
            }
        }

 private void button6_Click(object sender, EventArgs e)
        {
            DataTable dataTable = new DataTable();
            dataTable = Csv2DT.csv2dt(this.textBox1.Text, 0, dataTable);//取文本框中的path
            String Text = dataTable.Rows[1]["物料编码"].ToString();//用于测试是不是读取成功
            NPOIoutputexcel.ExportToExcelData(dataTable, "sheet1");
        }

class Csv2DT
    {
        /// <summary>
        /// 将Csv读入DataTable
        /// </summary>
        /// <param name="filePath">csv文件路径</param>
        /// <param name="n">表示第n行是字段title,第n+1行是记录开始</param>
        /// <param name="k">可选参数表示最后K行不算记录默认0</param>
        public static DataTable csv2dt(string filePath, int n, DataTable dt) //这个dt 是个空白的没有任何行列的DataTable
        {
            String csvSplitBy = "(?<=^|,)(\"(?:[^\"]|\"\")*\"|[^,]*)";
            StreamReader reader = new StreamReader(filePath, System.Text.Encoding.Default, false);
            int i = 0, m = 0;
            reader.Peek();
            while (reader.Peek() > 0)
            {
                m = m + 1;
                string str = reader.ReadLine();
                if (m >= n + 1)
                {
                    if (m == n + 1) //如果是字段行，则自动加入字段。
                    {
                        MatchCollection mcs = Regex.Matches(str, csvSplitBy);
                        foreach (Match mc in mcs)
                        {
                            dt.Columns.Add(mc.Value); //增加列标题
                        }
                    }
                    else
                    {
                        MatchCollection mcs = Regex.Matches(str, "(?<=^|,)(\"(?:[^\"]|\"\")*\"|[^,]*)");
                        i = 0;
                        System.Data.DataRow dr = dt.NewRow();
                        foreach (Match mc in mcs)
                        {
                            dr[i] = mc.Value;
                            i++;
                        }
                        dt.Rows.Add(dr);  //DataTable 增加一行     
                    }
                }
            }
            return dt;
        }
     }

 static class NPOIoutputexcel
    {
        public static void ExportToExcelData(DataTable DataTable, string sheetName)
        {
            SaveFileDialog fileDialog = new SaveFileDialog();
            //fileDialog.Filter = "Excel(97-2003)|*.xls|Excel(2007-2013)|*.xlsx";
            fileDialog.Filter = "Excel|*.xls|Excel|*.xlsx";
            if (fileDialog.ShowDialog() == System.Windows.Forms.DialogResult.Cancel)
            {
                return;
            }
            //IWorkbook workbook = new XSSFWorkbook();
            //1、基于NPOI创建工作簿及工作表对象
            HSSFWorkbook hssf = new HSSFWorkbook();//2007以下版本
            //XSSFWorkbook xssf = new XSSFWorkbook();//2007以上版本
            //根据不同的excel版本创建不同干的工作簿
            IWorkbook workbook = null;

            workbook = hssf;

            ISheet sheet = workbook.CreateSheet(sheetName);
            IRow rowHead = sheet.CreateRow(0);

            //填写表头
            for (int i = 0; i < DataTable.Columns.Count; i++)
            {
                rowHead.CreateCell(i, CellType.String).SetCellValue(DataTable.Columns[i].ColumnName.ToString());
            }
            //填写内容
            for (int i = 0; i < DataTable.Rows.Count; i++)
            {
                IRow row = sheet.CreateRow(i + 1);
                for (int j = 0; j < DataTable.Columns.Count; j++)
                {
                    row.CreateCell(j, CellType.String).SetCellValue(DataTable.Rows[i][j].ToString());
                }
            }

            for (int i = 0; i < DataTable.Columns.Count; i++)
            {
                sheet.AutoSizeColumn(i);
            }

            using (FileStream stream = File.OpenWrite(fileDialog.FileName))
            {
                workbook.Write(stream);
                stream.Close();
            }
            MessageBox.Show("导出数据成功!", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
            GC.Collect();
        }

    }