重新同步时未显示图片

Question

我做我的第一个Xamarin跨平台应用程序。

我正在尝试显示一张图片，该图片来自我编写的TCP服务器。

起初，我尝试在每次请求站点时重新加载图片。但是由于同步读取流，因此该站点需要较长的时间来加载，并且还阻塞了UI。因此，我尝试异步读取网络流。但是，所以我没有显示图片。另外，我不确定所显示的数据是否完整。

public static async Task<bool> ReceivePicture(string sTCP, int iPort, Byte[] bData)
    {
        TcpClient client = new TcpClient   // Creates a TCP Client
        {
            ReceiveTimeout = 800,
            SendTimeout = 800
        };
        client = new TcpClient(sTCP, iPort); //Trys to Connect

        await client.ConnectAsync(sTCP, iPort);
        if (!client.Connected)
            return false;

        NetworkStream serverStream = client.GetStream();

        string sSend = "DATA_PICTURE";

        byte[] outStream = Encoding.UTF8.GetBytes(sSend);
        serverStream.Write(outStream, 0, outStream.Length);
        serverStream.Flush();

        byte[] inStream = new byte[32];
        int j = 0;

        var ack = await serverStream.ReadAsync(inStream, j, inStream.Length);

        UTF8Encoding encoder = new UTF8Encoding();

        string sMessage = encoder.GetString(inStream, 0, ack);

        string[] words = sMessage.Split(';');
        Int32.TryParse(words[1], out int iPicSize);

        sSend = "OK";
        outStream = Encoding.UTF8.GetBytes(sSend);
        serverStream.Write(outStream, 0, outStream.Length);
        serverStream.Flush();

        var encoding = Encoding.UTF8;
        var i = 0;
        byte[] inStreamPic = new byte[iPicSize];
        var sb = new StringBuilder();

        //while (!serverStream.DataAvailable)
        //{
        //}

        //while (serverStream.DataAvailable)
        //{
        //    serverStream.Read(inStreamPic, j, 1);
        //    j++;
        //}

        while ((i = await serverStream.ReadAsync(inStreamPic, 0, inStreamPic.Length)) != 0)
        {
            sb.Append(encoding.GetString(inStreamPic, 0, i));
            if (!serverStream.DataAvailable) break;
        }

        img.Source = ImageSource.FromStream(() => new MemoryStream(inStreamPic));
        bData = inStreamPic;

        //var sFileName = Path.Combine(App.FolderPath, "Screen.png");
        //File.WriteAllBytes(sFileName, bData);
        //ImageConverter ic = new ImageConverter();


        //File.WriteAllBytes(sFileName, bData);
        //sFileName = img. ;
        client.GetStream().Close();
        client.Close();
        return true;
    }