给我一个 C# Npoi导出word excel 的helper

以下是一个示例 C# Npoi 导出 Word 和 Excel 的 Helper 类：

using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;
using NPOI.XSSF.UserModel;
using NPOI.XWPF.UserModel;
using System.Collections.Generic;
using System.IO;

namespace MyProject.Helpers
{
    public class NpoiHelper
    {
        /// <summary>
        /// 导出 Excel
        /// </summary>
        /// <param name="data">数据</param>
        /// <param name="filePath">文件路径</param>
        public static bool ExportExcel(List<List<string>> data, string filePath)
        {
            IWorkbook workbook;
            if (Path.GetExtension(filePath) == ".xls")
            {
                workbook = new HSSFWorkbook();
            }
            else
            {
                workbook = new XSSFWorkbook();
            }

            ISheet sheet = workbook.CreateSheet("Sheet1");
            for (int i = 0; i < data.Count; i++)
            {
                IRow row = sheet.CreateRow(i);
                for (int j = 0; j < data[i].Count; j++)
                {
                    ICell cell = row.CreateCell(j);
                    cell.SetCellValue(data[i][j]);
                }
            }

            using (FileStream stream = new FileStream(filePath, FileMode.Create, FileAccess.Write))
            {
                workbook.Write(stream);
            }

            return true;
        }

        /// <summary>
        /// 导出 Word
        /// </summary>
        /// <param name="data">数据</param>
        /// <param name="filePath">文件路径</param>
        public static bool ExportWord(List<string> data, string filePath)
        {
            XWPFDocument doc = new XWPFDocument();
            XWPFParagraph p = doc.CreateParagraph();
            foreach (string s in data)
            {
                XWPFRun r = p.CreateRun();
                r.SetText(s);
                r.AddCarriageReturn();
            }

            using (FileStream stream = new FileStream(filePath, FileMode.Create, FileAccess.Write))
            {
                doc.Write(stream);
            }

            return true;
        }
    }
}

使用示例：

// 导出 Excel
List<List<string>> data = new List<List<string>>()
{
    new List<string> { "姓名", "年龄", "性别" },
    new List<string> { "张三", "18", "男" },
    new List<string> { "李四", "20", "女" }
};
NpoiHelper.ExportExcel(data, "D:\\test.xlsx");

// 导出 Word
List<string> data = new List<string>()
{
    "这是一段文本。",
    "这是另一段文本。"
};
NpoiHelper.ExportWord(data, "D:\\test.docx");

注意，使用该 Helper 类需要安装 NPOI NuGet 包。