.net core 文件下载，.net core excel下载

代码如下,非常简单实用：

private readonly IWebHostEnvironment _webHostEnvironment;
public PhoneController(IWebHostEnvironment webHostEnvironment)
{
    _webHostEnvironment = webHostEnvironment;
}
public IActionResult DownloadFile()
{
    var filePath = "/app/tnblog_beta.apk";
    var fileName = "tnblog_beta.apk";
    /* FileStream fs = new FileStream(_webHostEnvironment.WebRootPath + filePath, FileMode.OpenOrCreate);
                fs.Close();*/
    return File(new FileStream(_webHostEnvironment.WebRootPath + filePath, FileMode.Open), 
    "application/octet-stream", fileName);
}

还有这种路径写法：

/// <summary>
/// 模板下载
/// </summary>
/// <returns></returns>
public FileResult DownloadTemplate()
{
    string baseDir = Path.Combine(Directory.GetCurrentDirectory(), "wwwroot");
    string filePath = baseDir + "/template/filetemplate.xls";
    string fileName = "filetemplate.xls";
    return File(new FileStream(filePath, FileMode.Open),
    "application/octet-stream", fileName);
}

使用response来输出已经存在了的附件文件

using (FileStream fs = new FileStream(filePath, FileMode.Open))
{
    byte[] bytes = new byte[(int)fs.Length];
    fs.Read(bytes, 0, bytes.Length);
    fs.Close();
    //Response.ContentEncoding = System.Text.Encoding.GetEncoding("UTF-8");
    Response.ContentType = "application/octet-stream;charset=UTF-8";;
    string newName = Guid.NewGuid().ToString().Replace("-", "");
    Response.Headers.Add("Content-Disposition", "attachment; filename=" + newName + "." + tnblogResourceDTO.Suffix);
    Response.BodyWriter.WriteAsync(bytes);
    Response.BodyWriter.FlushAsync();
}

也可以使用response来输出附件文件，例如下载内存中构建的excel表格

//把内存流做为文件下载中转
MemoryStream memoryStream = new MemoryStream();
workbook.Write(memoryStream);
//Response.ContentEncoding = System.Text.Encoding.GetEncoding("UTF-8");
Response.ContentType = "application/octet-stream;charset=UTF-8"; ;
string newName = Guid.NewGuid().ToString().Replace("-", "");
Response.Headers.Add("Content-Disposition", "attachment;filename=" + WebUtility.UrlEncode("用户信息表.xls"));
//Response.Headers.Add("Content-Disposition", "attachment;filename=用户信息表.xls");
Response.BodyWriter.WriteAsync(memoryStream.ToArray());
Response.BodyWriter.FlushAsync();

这里下载名称做了一下url编码不然遇到中文下载会报错：InvalidOperationException: Invalid non-ASCII or control character in header: 0x7528