excel 导入

 public static DataTable ExcelToDataTable(string fileName, string sheetName, bool isFirstRowColumn)
        {
            IWorkbook workbook = null;
            ISheet sheet = null;
            DataTable data = new DataTable("DataTable");
            int startRow = 0;

            string fileExt = Path.GetExtension(fileName);    //获取文件的后缀名
            FileStream fs = new FileStream(fileName, FileMode.Open, FileAccess.Read);
            if (fileExt == ".xlsx") // 2007版本
            {
                workbook = new XSSFWorkbook(fs);
            }
            else if (fileExt == ".xls") // 2003版本
            {
                workbook = new HSSFWorkbook(fs);
            }
            if (sheetName != null)
            {
                sheet = workbook.GetSheet(sheetName);
                if (sheet == null) //如果没有找到指定的sheetName对应的sheet，则尝试获取第一个sheet
                {
                    sheet = workbook.GetSheetAt(0);
                }
            }
            else
            {
                sheet = workbook.GetSheetAt(0);
            }
            if (sheet != null)
            {
                IRow firstRow = sheet.GetRow(0);
                int cellCount = firstRow.LastCellNum; //一行最后一个cell的编号 即总的列数
                if (isFirstRowColumn)
                {
                    for (int i = firstRow.FirstCellNum; i < cellCount; ++i)
                    {
                        ICell cell = firstRow.GetCell(i);
                        if (cell != null)
                        {
                            string cellValue = cell.StringCellValue;
                            if (cellValue != null)
                            {
                                DataColumn column = new DataColumn(cellValue);
                                data.Columns.Add(column);
                            }
                        }
                    }
                    startRow = sheet.FirstRowNum + 1;
                }
                else
                {
                    startRow = sheet.FirstRowNum;
                }
                //最后一列的标号
                int rowCount = sheet.LastRowNum;
                DataRow dataRow;
                for (int i = startRow; i <= rowCount; ++i)
                {
                    IRow row = sheet.GetRow(i);
                    if (row == null)
                    {
                        continue; //没有数据的行默认是null　　
                    }
                    dataRow = data.NewRow();
                    for (int j = row.FirstCellNum; j < cellCount; ++j)
                    {
                        if (row.GetCell(j).CellType == CellType.Numeric)
                        {
                            dataRow[j] = row.GetCell(j).NumericCellValue;
                        }
                        else
                        {
                            dataRow[j] = row.GetCell(j).ToString();
                        }
                    }
                    data.Rows.Add(dataRow);
                }
            }
            return data;
        }

调用： 

  dt = ExcelHelper.ExcelToDataTable(txtFilePath.Text, "", true);

//txtFilePath.Text：上传路径
上传：

private void btnOpen_Click(object sender, EventArgs e)
        {
            OpenFileDialog fileDialog = new OpenFileDialog();
            fileDialog.Title = "请打开Excel文件";
            fileDialog.Filter = "(EXCEL 文件)|*.xls;*.xlsx"; //设置要选择的文件的类型
            if (fileDialog.ShowDialog() == DialogResult.OK)
            {
                txtFilePath.Text = fileDialog.FileName;//返回文件的完整路径
            }
        }