C# vs2017 winForm 用NOPI导入Excel文件到datagridview

using NPOI.SS.UserModel;
using NPOI.XSSF.UserModel;
using NPOI.HSSF.UserModel;
using System.IO;

using System;
using System.Windows.Forms;
using NPOI.SS.UserModel;
using NPOI.XSSF.UserModel;
using NPOI.HSSF.UserModel;
using System.IO;

namespace InputExcelTest
{
    public partial class Form_SelectFile : Form
    {
        public Form_SelectFile()
        {
            InitializeComponent();
        }

        private void BtnSelectFile_Click(object sender, EventArgs e)
        {//选择文件
            openFileDialog1.Filter= "XLS文件|*.xls|XLSX文件|*.xlsx";//筛选文件类型
            openFileDialog1.FileName = "";
            if (openFileDialog1.ShowDialog() == DialogResult.OK)
            {
                InputWorkbook(openFileDialog1.FileName);//执行导入
            }
            openFileDialog1.Dispose();
        }

        private void BtnCancel_Click(object sender, EventArgs e)
        {
            Close();
        }
        
        //导入工作簿
        private void InputWorkbook(string filePath)
        {
            if (filePath != "")
            {
                try
                {
                    string fileType = filePath.Substring(filePath.LastIndexOf(".") + 1);//取得文件后缀
                    FileStream fs = new FileStream(filePath, FileMode.Open, FileAccess.Read);//创建文件流
                    bool isXls = true;//判断文件类型
                    if (fileType == "xlsx")
                    {
                        isXls = false;
                    }
                    IWorkbook workbook = CreateWorkbook(isXls, fs);//创建工作簿
                    ISheet sheet = workbook.GetSheetAt(0);//取得第一个工作表
                    int rowCount = sheet.LastRowNum + 1;//取得行数
                    int colCount = sheet.GetRow(0).LastCellNum;//取得列数
                    //初始化datagridview1
                    dataGridView1.Rows.Clear();
                    dataGridView1.Columns.Clear();
                    for (int c = 0; c < colCount; c++)//遍历Excel第一行，生成dataGridView1列名
                    {
                        ICell cell = sheet.GetRow(0).GetCell(c);
                        dataGridView1.Columns.Add(c.ToString() + cell.ToString(), cell.ToString());
                    }

                    for (int r = 1; r < rowCount; r++)//遍历Excel其他行,生成dataGridView1单元格内容
                    {//遍历Excel行,从第二行开始
                        IRow row = sheet.GetRow(r);
                        int index = dataGridView1.Rows.Add();
                        colCount = row.LastCellNum;
                        for (int c = 0; c < colCount; c++)
                        {//遍历每个单元格,将单元格内容填入dataGridView1单元格中
                            ICell cell = row.GetCell(c);
                            if (cell == null)//如果该单元格没有内容，跳过
                            {
                                continue;
                            }
                            dataGridView1.Rows[index].Cells[c].Value = cell.ToString();
                        }
                    }

                }
                catch (Exception ex)
                {
                    MessageBox.Show("导入失败: " + ex.Message);

                }
            }
            else
            {
                MessageBox.Show("请选择Excel文件");
            }
        }
        //创建工作簿
        private static IWorkbook CreateWorkbook(bool isXLS, FileStream fs)
        {
            if (isXLS)
            {
                return new HSSFWorkbook(fs);
            }
            else
            {
                return new XSSFWorkbook(fs);
            }
        }
    }
}