如何在异步套接字中接收完整的屏幕截图？

Question

我有一个Java android代码，它将数据（图像或文本）发送到C#应用程序，以接收我正在使用异步套接字的这些数据。但是存在一个与BeginReceive()功能有关的问题，就是在发送图像时没有接收到完整的数据。那么，如何使一种“循环”来接收完整的数据并在Picturebox上显示图像之后（例如）？

形成

private Listener listener;
private Thread startListen;

private Bitmap _buffer;

public frmMain()
{
  InitializeComponent();
}

private void serverReceivedImage(Client client, byte[] image)
{
    try
    {
        byte[] newImage = new byte[image.Length - 6];

        Array.Copy(image, 6, newImage, 0, newImage.Length);

            using (var stream = new MemoryStream(newImage))
            {
                using (var msInner = new MemoryStream())
                {

                  stream.Seek(2, SeekOrigin.Begin);

                  using (DeflateStream z = new DeflateStream(stream, CompressionMode.Decompress))
                  {
                    z.CopyTo(msInner);
                  }

                  msInner.Seek(0, SeekOrigin.Begin);

                  var bitmap = new Bitmap(msInner);
                  Invoke(new frmMain.ImageCompleteDelegate(ImageComplete), new object[] { bitmap });
                }
            }
    }
     catch (Exception)
     {
        System.Diagnostics.Process.GetCurrentProcess().Kill();
     }
}

private delegate void ImageCompleteDelegate(Bitmap bitmap);
private void ImageComplete(Bitmap bitmap)
{
   if (_buffer != null)
       _buffer.Dispose();

       _buffer = new Bitmap(bitmap);
       pictureBox1.Size = _buffer.Size;
       pictureBox1.Invalidate();
}

private void pictureBox1_Paint(object sender, PaintEventArgs e)
{
  if (_buffer == null) return;
      e.Graphics.DrawImage(_buffer, 0, 0);
}

private void startToolStripMenuItem_Click(object sender, EventArgs e)
{
  startListen = new Thread(listen);
  startListen.Start();
}

private void listen()
{
  listener = new Listener();
  listener.BeginListen(101);
  listener.receivedImage += new Listener.ReceivedImageEventHandler(serverReceivedImage);

  startToolStripMenuItem.Enabled = false;
}

听众

class Listener
{

    private Socket s;
    public List<Client> clients;

    public delegate void ReceivedImageEventHandler(Client client, byte[] image);
    public event ReceivedImageEventHandler receivedImage;

    private bool listening = false;

    public Listener()
    {
        clients = new List<Client>();
        s = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
    }

    public bool Running
    {
        get { return listening; }
    }

    public void BeginListen(int port)
    {
        s.Bind(new IPEndPoint(IPAddress.Any, port));
        s.Listen(100);
        s.BeginAccept(new AsyncCallback(AcceptCallback), s);
        listening = true;
    }

    public void StopListen()
    {
        if (listening == true)
        {
            s.Close();
            listening = false;
        }
    }

    void AcceptCallback(IAsyncResult ar)
    {
        Socket handler = (Socket)ar.AsyncState;
        Socket sock = handler.EndAccept(ar);
        Client client = new Client(sock);
        clients.Add(client);

        sock.BeginReceive(client.buffer, 0, client.buffer.Length, SocketFlags.None, new AsyncCallback(ReadCallback), client);

        client.Send("REQUEST_PRINT" + Environment.NewLine); 

        handler.BeginAccept(new AsyncCallback(AcceptCallback), handler);
    }

    void ReadCallback(IAsyncResult ar)
    {

        Client client = (Client)ar.AsyncState;
        try
        {
            int rec = client.sock.EndReceive(ar);
            if (rec != 0)
            {
                string data = Encoding.UTF8.GetString(client.buffer, 0, rec);

                if (data.Contains("SCREEN"))
                { 
                    byte[] bytes = Encoding.UTF8.GetBytes(data);
                    receivedImage(client, bytes);
                }
                else // not is a image, is a text
                {
                    // prepare text to show in TextBox
                }
            }
            else
            {
                Disconnected(client);
                return;
            }

            client.sock.BeginReceive(client.buffer, 0, client.buffer.Length, SocketFlags.None, new AsyncCallback(ReadCallback), client);
        }
        catch
        {
            Disconnected(client);
            client.sock.Close();
            clients.Remove(client);
        }
    }

}

客户

class Client
{
    public Socket sock;
    public byte[] buffer = new byte[8192];

    public Client(Socket sock)
    {
        this.sock = sock;
    }

    public void Send(string data)
    {
        byte[] buffer = Encoding.ASCII.GetBytes(data);
        sock.BeginSend(buffer, 0, buffer.Length, SocketFlags.None, new AsyncCallback((ar) =>
        {
            sock.EndSend(ar);
        }), buffer);
    }
}

---

Android代码

private byte[] compress(byte[] data) {

    Deflater deflater = new Deflater();
    deflater.setInput(data);
    ByteArrayOutputStream outputStream = new ByteArrayOutputStream(data.length);
    deflater.finish();
    byte[] buffer = new byte[1024];
    while (!deflater.finished()) {
        int count = deflater.deflate(buffer);
        outputStream.write(buffer, 0, count);
    }
    outputStream.close();
    byte[] output = outputStream.toByteArray();

    return output;
}

public static DataOutputStream dos;
public static byte[] array;

ByteArrayOutputStream bos = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.PNG, 100, bos);
array = compress(bos.toByteArray());

//...

dos = new DataOutputStream(SocketBackgroundService.clientSocket.getOutputStream());
byte[] header = ("SCREEN").getBytes(StandardCharsets.UTF_8);
byte[] dataToSend = new byte[header.length + array.length];
System.arraycopy(header, 0, dataToSend, 0, header.length);
System.arraycopy(array, 0, dataToSend, header.length, array.length);
dos.writeInt(dataToSend.length);
dos.write(dataToSend, 0, dataToSend.length);

dos.flush();

---

版

我总是在这一行中收到错误的无效参数

var bitmap = new Bitmap(msInner);

在这里使用压缩也一样

z.CopyTo(msInner);

IvalidDataException

分别在ServerReceivedImage（）方法上。

使用这个

File.WriteAllBytes(Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.MyPictures), "image.png"), newImage);

我注意到仅接收15KB（不使用压缩的文件大小）。