用.Net Core2和EPPlus下载excel文件

using OfficeOpenXml;
using System.IO;

// 创建一个新的Excel文件
ExcelPackage.LicenseContext = LicenseContext.NonCommercial;
using (var package = new ExcelPackage())
{
    // 添加一个工作表
    var worksheet = package.Workbook.Worksheets.Add("Sheet1");

    // 添加数据到工作表
    worksheet.Cells["A1"].Value = "姓名";
    worksheet.Cells["B1"].Value = "年龄";
    worksheet.Cells["A2"].Value = "张三";
    worksheet.Cells["B2"].Value = 25;

    // 保存Excel文件
    FileInfo fileInfo = new FileInfo("path/to/excel/file.xlsx");
    package.SaveAs(fileInfo);
}

[HttpGet]
public async Task<IActionResult> DownloadExcelFile()
{
    // 文件路径
    var filePath = "path/to/excel/file.xlsx";
    // 读取文件内容
    var content = await File.ReadAllBytesAsync(filePath);
    // 设置Content-Disposition头部信息，指定文件名
    var fileName = "file.xlsx";
    var contentDisposition = new System.Net.Mime.ContentDisposition
    {
        FileName = fileName,
        Inline = false
    };
    Response.Headers.Add("Content-Disposition", contentDisposition.ToString());
    // 返回文件内容
    return File(content, "application/octet-stream");
}