Csharp HttpClient，上传文件时实现进度

我正在开发一款UWP应用程序，它使用自定义API方法将文件上传到服务器.文件上传本身是正常的，但我在上传过程中执行进度跟踪时遇到了问题.我try 了几种方法，包括创建一个定制的ProgressStreamContent类，但似乎都不起作用

以下是没有跟踪进度的原始API方法:

public async Task<ApiResult<FileUploadResult>> UploadFile(string metadata, Stream content, string sessionId, string treeId, string nodeId,Action<long, long> progressCallback = null, CancellationToken? cancellationToken = null)
        {
            string url = $"{_httpHelper.GetFileUploadsBaseUrl()}/{sessionId}/{treeId}/{nodeId}";

            MultipartFormDataContent multipartContent = new MultipartFormDataContent
            {
                { new StringContent(metadata), "metadata" },
                { new StreamContent(content), "content" }

            };

            ApiResult<FileUploadResult> result = await _httpHelper.PostAsync<FileUploadResult>(url, multipartContent, cancellationToken);

            return result;

        }

下面是我使用定制的ProgressStreamContent类添加进度跟踪的try :

    public class ProgressStreamContent : HttpContent
    {


        private const int defaultBufferSize = 5 * 4096;

        private HttpContent content;
        private int bufferSize;
        //private bool contentConsumed;
        private Action<long, long> progress;

        public ProgressStreamContent(HttpContent content, Action<long, long> progress) : this(content, defaultBufferSize, progress) { }

        public ProgressStreamContent(HttpContent content, int bufferSize, Action<long, long> progress)
        {
            if (content == null)
            {
                throw new ArgumentNullException("content");
            }
            if (bufferSize <= 0)
            {
                throw new ArgumentOutOfRangeException("bufferSize");
            }

            this.content = content;
            this.bufferSize = bufferSize;
            this.progress = progress;

            foreach (var h in content.Headers)
            {
                this.Headers.Add(h.Key, h.Value);
            }
        }

        protected override Task SerializeToStreamAsync(Stream stream, TransportContext context)
        {

            return Task.Run(async () =>
            {
                var buffer = new Byte[this.bufferSize];
                long size;
                TryComputeLength(out size);
                var uploaded = 0;


                using (var sinput = await content.ReadAsStreamAsync())
                {
                    while (true)
                    {
                        var length = sinput.Read(buffer, 0, buffer.Length);
                        if (length <= 0) break;

         
                        uploaded += length;
                        progress?.Invoke(uploaded, size);

                        stream.Write(buffer, 0, length);
                        stream.Flush();
                    }
                }
                stream.Flush();
            });
        }

        protected override bool TryComputeLength(out long length)
        {
            length = content.Headers.ContentLength.GetValueOrDefault();
            return true;
        }

        protected override void Dispose(bool disposing)
        {
            if (disposing)
            {
                content.Dispose();
            }
            base.Dispose(disposing);
        }
}

下面是我如何使用它的，我创建了DelegatingHandler来处理进度

 public class ProgressMessageHandler : DelegatingHandler
    {
        private Action<long, long> _onUploadProgress;

        public event Action<long, long> HttpProgress
        {
            add => _onUploadProgress += value;
            remove => _onUploadProgress -= value;
        }
        public ProgressMessageHandler(HttpMessageHandler innerHandler) : base(innerHandler)
        {
        }
        protected async override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
        {
            var progressContent = new ProgressStreamContent(
                request.Content,
                4096,
                (sent, total) =>
                {
                    Console.WriteLine("Uploading {0}/{1}", sent, total);
                    OnUploadProgress(sent, total);
                });
            request.Content = progressContent;
            return await base.SendAsync(request, cancellationToken);
        }
        private void OnUploadProgress(long bytesTransferred, long totalBytes)
        {
            _onUploadProgress?.Invoke(bytesTransferred, totalBytes);
        }
    }

并将Api函数更新为

        public async Task<ApiResult<FileUploadResult>> UploadFile(string metadata, Stream content, string sessionId, string treeId, string nodeId,Action<long, long> progressCallback = null, CancellationToken? cancellationToken = null)
        {
            string url = $"{_httpHelper.GetFileUploadsBaseUrl()}/{sessionId}/{treeId}/{nodeId}";

            MultipartFormDataContent multipartContent = new MultipartFormDataContent
            {
                { new StringContent(metadata), "metadata" },
                { new ProgressStreamContent(new StreamContent(content), progressCallback), "content" }

            };

            ApiResult<FileUploadResult> result = await _httpHelper.PostAsync<FileUploadResult>(url, multipartContent, cancellationToken);

            return result;

        }

我正在寻求关于如何在我的UWP应用程序中正确执行文件上传过程中的进度跟踪的指导.任何见解或替代方法都将受到极大的赞赏.谢谢!