Question

I want to sent DataTable from Server to Client using XML file in C#. I have used following code at server side

DataSet ds = new DataSet();
ds.WriteXml(nw, XmlWriteMode.WriteSchema);

where nw is NetworkStream at Server

and following code is at Client side

DataSet ds = new DataSet();
ds.ReadXml(clientSockStream, XmlReadMode.ReadSchema);

The server is sending data but at client side the program gets halted.
Server Side:

tcpserver = new TcpListener(IPAddress.Any, 4444);
tcpserver.Start();
Socket serverSocket = tcpserver.AcceptSocket(); // accepting connection
    if (serverSocket.Connected)
    {
        serversockstream = new NetworkStream(serverSocket);
        serverStreamReader = new StreamReader(serversockstream);
        serverStreamWriter = new StreamWriter(serversockstream);
        handleClinet client = new handleClinet(); 
        client.startClient(serverStreamReader, serversockstream,serverStreamWriter);
    }

    public void startClient(StreamReader streamReader, NetworkStream ser, StreamWriter streamWriter)
    {
        this.sread = streamReader;
        this.swrite = streamWriter;
        this.nwstram = ser;
        Thread ctThread = new Thread(handleClients);
        ctThread.Start();
    }

    private void handleClients()
    {
        // Creating Dummy DataTable to send to Client...
        DataSet ds = new DataSet();
        DataTable d = new DataTable();
        d.Columns.Add("Name");
        d.Columns.Add("City");
        d.Rows.Add("John","USA");

        ds.Tables.Add(d);

        try
        {    

            while ((true))
            {
                String mystr = sread.ReadLine();
                if (mystr.Equals("sendTable"))
                    break;
            }
            swrite.WriteLine("done");
            swrite.Flush();
            if(nwstram.CanWrite)
            {
                MessageBox.Show("it can write...");
                ds.WriteXml(nwstram, XmlWriteMode.IgnoreSchema);
            }
            nwstram.Flush();
            MessageBox.Show("XML Sent");

        }

Client Side:

    tcpClient = new TcpClient("127.0.0.1", 4444);

    IPHostEntry ip = Dns.GetHostEntry("127.0.0.1");
    //get a network stream from server
    clientSockStream = tcpClient.GetStream();
    clientStreamReader = new StreamReader(clientSockStream);
    clientStreamWriter = new StreamWriter(clientSockStream);

    private void button2_Click(object sender, EventArgs e)
    {
        try
        {
            clientStreamWriter.WriteLine("sendTable");
            clientStreamWriter.Flush();
            DataSet ds = new DataSet();
            String str = "";
            while (true)
            {
                str = clientStreamReader.ReadLine();
                if (str.Equals("done"))
                    break;

            }
            //MessageBox.Show("Client :" + str);
            if (clientSockStream.CanRead)
            {
                ds.ReadXml(clientSockStream, XmlReadMode.IgnoreSchema);
            }
        }
        dataGridView1.DataSource = ds.Tables[0];
    }

Assume that all catch blocks and necessary variables have declared ..
Plz reply..

Answer 1

I’m not sure that I am seeing all of your code, but here is an example of what I would do if I HAD to use TcpSockets instead of WCF.

SERVER SIDE

public void StartServer()
{
    TcpListener listener = null;
    TcpClient client = null;
    NetworkStream nwStream = null; 

    try
    {
        listener = new TcpListener(IPAddress.Any, 4444);
        listener.Start();
    }
    catch(Exception ex)
    { Console.WriteLine(ex.Message); }

    byte[] buffer = new byte[1024];

    try
    {
        bool waiting = true;

        while(waiting)
        {
            if(listener.Pending())
            {

                client = listener.AcceptTcpClient();
                nwStream = client.GetStream();

                using(var ms = new MemoryStream())
                {
                    CreateDataSet().WriteXml(ms);
                    ms.Position = 0;

                    int read = 0;
                    while((read = ms.Read(buffer, 0, 1024)) != 0)
                    {
                        nwStream.Write(buffer, 0, read);
                    }
                }
                nwStream.Flush();
                nwStream.Close();
                client.Close();
                waiting = false;
            }
        }
    }
    catch(Exception ex)
    {
       Console.WriteLine(ex.Message);
    }
}

private DataSet CreateDataSet()
{
    //Create your dataset here and return something
}

CLIENT SIDE

public DataSet GetDataSet()
{
    DataSet ds = new DataSet();
    TCPClient client = null;
    NetworkStream nwStream = null;

    try
    {
        client = new TcpClient("127.0.0.1", 4444);
        nwStream = client.GetStream();

        using(var ms = new MemoryStream())
        {
            byte[] buffer = new byte[1024];
            int read = 0;
            while((read = nwStream.Read(buffer, 0, 1024)) != 0)
            {
                ms.Write(buffer, 0, read);
            }
            ms.Position = 0;

            ds.ReadXml(ms);
        }
    }
    finally
    {
        nwStream.Close();
        client.Close();
    }

    return ds;
}

I wouldn’t say that this will work exactly as you want, but with some modification that should be a good start. However, I would highly suggest looking into WCF (I’m a huge propponent) because here is the framework of your same service in some code.

WCF SERVER SIDE

[ServiceContract]
public interface IDataService
{
    [OperationContract]
    DataSet GetData();
}

public class DataService: IDataService
{
    public DataSet GetData()
    {
        //return some dataset here
    }
}

WCF CLIENT SIDE

private DataSet GetDataSet()
{
    DataSet ds;

    //This would be utilizing some gerated code, or you can make your own client
    var client = new DataServiceClient(someEndPoint, someBinding);
    client.Open();

    ds = client.GetData();

    client.Close();
    return ds;
}

Again, that is not totally working code, but is just a sample of why WCF is so popular over writing your own crazy through sockets. If you are looking to stay language neutral, you could even upgrade to http sockets instead and it will still work with Java, so long as it is SOAP standard (there are a few features like reliable messaging that are not compatible with anything other than .NET).