ASP.NET WebAPI 文件下载

此方法返回文件流 如果客户端是浏览器会弹出文件保存对话框让用户下载保存

    [HttpGet]
    public IActionResult DownloadPostcodeImportTemplateFile()
    {
        var filePath = Path.Combine("StaticFiles", "ExcelTemplate", "postCodeImportTemplate.xls");
        var fileName = Path.GetFileName(filePath);
        var fileStream = new FileStream(filePath, FileMode.Open);
        return File(fileStream, "application/octet-stream", fileName);
    }