c# - 自定义 ProgressableStreamContent 不起作用

Question

你好根据：https ://gist.github.com/HirbodBehnam/272aa5e4b82c2fb05583d095f2224861

我实现了这个：

我的电话：

public async Task<string> UploadFiles(FileInfo fileInfo)
    {
        string res = null; 

        using (var client = new HttpClient())
        using (var multiForm = new MultipartFormDataContent())
        {
            client.Timeout = TimeSpan.FromMinutes(5); // You may need this if you are uploading a big file

            var file = new ProgressableStreamContent(new StreamContent(File.OpenRead(fileInfo.FullName))
                , (sent, total) => {
                    //Console.SetCursorPosition(1, 0); // Remove last line
                    Console.WriteLine("\bUploading " + ((float)sent / total) * 100f);
                });

            multiForm.Add(file, fileInfo.Name, fileInfo.Name); // Add the file

            var uploadServiceBaseAdress = "http://10.0.2.2:44560/PostFiles/";

            var response = await client.PostAsync(uploadServiceBaseAdress, multiForm);
            Console.WriteLine(response.StatusCode);
            if (response.StatusCode == HttpStatusCode.OK)
            {
                res = await response.Content.ReadAsStringAsync();
                Console.WriteLine(res);

            }

            return res;
        }

我的课：可进步的流内容

internal class ProgressableStreamContent:HttpContent
{
    /// <summary>
    /// Lets keep buffer of 20kb
    /// </summary>
    private const int defaultBufferSize = 5 * 4096;

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

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

    public ProgressableStreamContent(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;

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

                    //System.Diagnostics.Debug.WriteLine($"Bytes sent {uploaded} of {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);
    }
}

它绑定在 ProgressableStreamContent 的构造函数中。然后回到我的上传文件方法，但是当它返回时它崩溃了：Operation not supported on this platform。

我认为有些东西我不明白，我没有找到任何与此相关的文档。那么你能解释一下怎么了吗？

标签： c#xamarinxamarin.formsxamarin.androidhttpclient

Answer 1

您可以尝试这样的事情：

using (var multiForm = new MultipartFormDataContent())
    {
      byte[] fileBytes = null;// your file
      var file = new ByteArrayContent(fileBytes);

       ...

      multiForm.Add(file, fileInfo.Name, fileInfo.Name); // Add the file
      var progressContent = new ProgressableStreamContent(multiForm,4096, (sent, total) => {
                //Console.SetCursorPosition(1, 0); // Remove last line
                Console.WriteLine("\bUploading " + ((float)sent / total) * 100f);
            });

       ...

      var response = await client.PostAsync(uploadServiceBaseAdress, progressContent );

       ...
    }