通过套接字或tcp发送类对象列表

Question

I'm trying to send a list of objects to another computer. I'm new to sockets and such but have tried quite a few things. In the end I always end up with errors and can't get past them.

The list of objects I'm sending are classes with functions, variables and properties. I have placed the [Serializable] at the top of this class.

Each time a client performs a certain action it will change the San_Change to true and start the client thread.

I've attached my code below, and any help would be appreciated.

        public void Create_Network_Thread(string Host_Or_Client)
    {
        //This creates a network thread and starts it.

        //Host
        if (Host_Or_Client == "Host")
        {
            Host_networkThread = new Thread(new ThreadStart(Host_Network_Thread_Start));
            Host_networkThread.Start();
        }
        //Client
        else
        {
            Client_networkThread = new Thread(new ThreadStart(Client_Network_Thread_Start));
            Client_networkThread.Start();
        }
    }


    private void Host_Network_Thread_Start()
    {

        try
        {
            TcpListener serverSocket = new TcpListener(8888);
            TcpClient clientSocket = default(TcpClient);

            serverSocket.Start();

            clientSocket = serverSocket.AcceptTcpClient();

            while (true)
            {
                object San_Object;

                NetworkStream networkStream = clientSocket.GetStream();

                byte[] bytesFrom = new byte[clientSocket.Available];

                networkStream.Read(bytesFrom, 0, clientSocket.Available);

                San_Object = ByteArrayToObject(bytesFrom);

                San_List = (List<San>)San_Object;



                byte[] sendBytes = ObjectToByteArray(San_Object);

                networkStream.Write(sendBytes, 0, sendBytes.Length);

                networkStream.Flush();
            }
        }
        catch (Exception e)
        {
            Console.WriteLine(e.ToString());
        }
    }



    private void Client_Network_Thread_Start()
    {
        while (true)
        {
            if (San_Change == true)
            {
                San_Change = false;

                try
                {
                    System.Net.Sockets.TcpClient clientSocket = new System.Net.Sockets.TcpClient();

                    object San_Object = San_List;

                    string cur_ip = "";

                    clientSocket.Connect(cur_ip, 8888);

                    NetworkStream serverStream = clientSocket.GetStream();

                    byte[] outStream = ObjectToByteArray(San_Object);

                    serverStream.Write(outStream, 0, outStream.Length);

                    serverStream.Flush();


                    byte[] inStream = new byte[(int)clientSocket.ReceiveBufferSize];

                    San_Object = ByteArrayToObject(inStream);

                    San_List = (List<San>)San_Object;
                }

                catch (Exception e)
                {

                    Console.WriteLine(e.ToString());
                }
            }
        }
    }

    private byte[] ObjectToByteArray(Object obj)
    {
        if (obj == null)
            return null;
        BinaryFormatter bf = new BinaryFormatter();
        MemoryStream ms = new MemoryStream();
        bf.Serialize(ms, obj);
        return ms.ToArray();
    }

    private Object ByteArrayToObject(byte[] arrBytes)
    {
        MemoryStream memStream = new MemoryStream();
        BinaryFormatter binForm = new BinaryFormatter();
        memStream.Write(arrBytes, 0, arrBytes.Length);
        memStream.Seek(0, SeekOrigin.Begin);
        Object obj = (Object)binForm.Deserialize(memStream);
        return obj;
    }

}

When ran this occurs:

Forgot to add this in, but when I run this as it is the code fails. Here is the information, hope this helps. Thanks again.

e   {System.Runtime.Serialization.SerializationException: Binary stream '0' does not contain a valid BinaryHeader. Possible causes are invalid stream or object version change between serialization and deserialization.
   at System.Runtime.Serialization.Formatters.Binary.__BinaryParser.Run()
   at System.Runtime.Serialization.Formatters.Binary.ObjectReader.Deserialize(HeaderHandler handler, __BinaryParser serParser, Boolean fCheck, Boolean isCrossAppDomain, IMethodCallMessage methodCallMessage)
   at System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Deserialize(Stream serializationStream, HeaderHandler handler, Boolean fCheck, Boolean isCrossAppDomain, IMethodCallMessage methodCallMessage)
   at System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Deserialize(Stream serializationStream)
   at San_Player_V2.Game.ByteArrayToObject(Byte[] arrBytes) in San_Player_V2\Game.cs:line 573
   at San_Player_V2.Game.Client_Network_Thread_Start() in San_Player_V2\Game.cs:line 477}   System.Exception {System.Runtime.Serialization.SerializationException}

Answer 1

The usual problems:

• not processing the return value of Read
• thinking that the available-bytes represents complete units of data
• the lack of logical framing (usually via a length-prefix)

Personally I'd also say that using BinaryFormatter is problematic, but that isn't the biggest issue.

See http://marcgravell.blogspot.com/2013/02/how-many-ways-can-you-mess-up-io.html

Answer 2

It seems to be that you're double double work/reinventing the wheel here, that is:

1. You convert an object to a byte array
2. You send it out through the stream.

How about instead you try something like that:

1. Chain your Socket to an ObjectOutputStream
2. Use the ObjectOutputStream to write the object out directly and let the standard APIs

handle serializing the object on your end and deserializing it on the other end (when you use ObjectInputStream to receive it).

Answer 3

So I think that I found my answer. What is convert the object to an xml then convert that xml to a string. send that string through the socket just as a string then on the other side reconvert it to xml then back to a object. I've attached a small example.

This is in the object and called to xml it.

        public string ToXML()
    {
        var stringwriter = new System.IO.StringWriter();
        var serializer = new XmlSerializer(this.GetType());
        serializer.Serialize(stringwriter, this);
        return stringwriter.ToString();
    }

This is called to convert the xml back to the object of your pick.

    public static Object_Name_Here LoadFromXMLString(string xmlText)
    {
        var stringReader = new System.IO.StringReader(xmlText);
        var serializer = new XmlSerializer(typeof(Object_Name_Here));
        return serializer.Deserialize(stringReader) as Object_Name_Here;
    }

That is what I'm doing if someone has a better idea please share with a good example.

Thank you!