如何通过HttpClient PostAsync方法将文件和参数上传到远程服务器？

Question

我正在尝试将文件从桌面应用程序上传到远程服务器.浏览SO一段时间后,这种方法似乎是最简洁的方法.问题是服务器端没有接收到参数.我错过了什么？

    private void AddFile(FileInfo fileInfo, int folderId)
    {
        using (var handler = new HttpClientHandler() {CookieContainer = _cookies})
        {
            using (var client = new HttpClient(handler) {BaseAddress = new Uri(_host)})
            {
                var requestContent = new MultipartFormDataContent();
                var fileContent = new StreamContent(fileInfo.Open(FileMode.Open));
                var folderContent = new StringContent(folderId.ToString(CultureInfo.InvariantCulture));
                requestContent.Add(fileContent, "file", "file");
                requestContent.Add(folderContent, "folderId", "folderId");

                client.PostAsync("/Company/AddFile", requestContent);
            }
        }
    }

编辑:这是服务器端期望的签名:

    [HttpPost]
    public ActionResult AddFile(HttpPostedFileBase file, int folderId)

Answer 1

经过大量的反复试验,我得到了它.有一些问题.1)引号中的参数名称预期2)我遗漏了一堆标题信息.这是工作代码.

    private void AddFile(FileInfo fileInfo, int folderId)
    {
        using (var handler = new HttpClientHandler() {CookieContainer = _cookies})
        {
            using (var client = new HttpClient(handler) {BaseAddress = new Uri(_host)})
            {
                var requestContent = new MultipartFormDataContent();
                var fileContent = new StreamContent(fileInfo.OpenRead());
                fileContent.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")
                    {
                        Name = "\"file\"",
                        FileName = "\"" + fileInfo.Name + "\""
                    };
                fileContent.Headers.ContentType =
                    MediaTypeHeaderValue.Parse(MimeMapping.GetMimeMapping(fileInfo.Name));
                var folderContent = new StringContent(folderId.ToString(CultureInfo.InvariantCulture));

                requestContent.Add(fileContent);
                requestContent.Add(folderContent, "\"folderId\"");

                var result = client.PostAsync("Company/AddFile", requestContent).Result;
            }
        }