npoi datatable导入excel时写入表头

可以使用NPOI的DataTable类来读取Excel文件，并将表头写入DataTable中。具体实现可以参考以下代码：

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

// 读取Excel文件
using (FileStream file = new FileStream("test.xlsx", FileMode.Open, FileAccess.Read))
{
    XSSFWorkbook workbook = new XSSFWorkbook(file);
    ISheet sheet = workbook.GetSheetAt(0);

    // 创建DataTable并添加列
    DataTable dt = new DataTable();
    IRow headerRow = sheet.GetRow(0);
    foreach (ICell headerCell in headerRow)
    {
        dt.Columns.Add(headerCell.ToString());
    }

    // 添加行数据
    for (int i = (sheet.FirstRowNum + 1); i <= sheet.LastRowNum; i++)
    {
        IRow row = sheet.GetRow(i);
        DataRow dataRow = dt.NewRow();

        for (int j = row.FirstCellNum; j < row.LastCellNum; j++)
        {
            if (row.GetCell(j) != null)
            {
                dataRow[j] = row.GetCell(j).ToString();
            }
        }

        dt.Rows.Add(dataRow);
    }
}