如何使用C#导出Excel文件

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using OfficeOpenXml;
using System.IO;

// 创建新的Excel包
using (ExcelPackage package = new ExcelPackage())
{
    // 在Excel包中创建一个工作簿
    ExcelWorkbook workbook = package.Workbook;
    if (workbook != null)
    {
        // 添加一个工作表
        ExcelWorksheet worksheet = workbook.Worksheets.Add("Sheet1");

        // 在工作表中填充数据
        worksheet.Cells["A1"].Value = "姓名";
        worksheet.Cells["B1"].Value = "年龄";

        worksheet.Cells["A2"].Value = "张三";
        worksheet.Cells["B2"].Value = 25;

        worksheet.Cells["A3"].Value = "李四";
        worksheet.Cells["B3"].Value = 30;

        // 自动调整列宽
        worksheet.Cells.AutoFitColumns();

        // 保存Excel文件
        FileInfo file = new FileInfo("output.xlsx");
        package.SaveAs(file);
    }
}

// 将Excel文件写入Response输出流，实现导出
using (MemoryStream memoryStream = new MemoryStream())
{
    using (FileStream fileStream = new FileStream("output.xlsx", FileMode.Open))
    {
        fileStream.CopyTo(memoryStream);
    }

    byte[] data = memoryStream.ToArray();
    Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
    Response.AddHeader("Content-Disposition", "attachment; filename=output.xlsx");
    Response.BinaryWrite(data);
    Response.End();
}