C# TcpClient/TcpListener / Full Duplex Communication / Sample

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C# TcpClient/TcpListener / Full Duplex Communication / Sample

Markus Freitag 3,791

Hello!

I have already asked. There must be a good example of Socket, TcpClient, TcpListener that does the following.

Duplex operation between client and server
Automatic reconnection
On 10 failed attempts, error message.
Read until the root element is received.
Read until the element root has been received, if necessary buffer it in a processing list and process it bit by bit

Send from Server to Client or the other way around.

<ROOT>
  <REQUESTS>
    <VARIANT name="TEST01022034">
      <PROGRAM name="87.1554.0_87.1554.0" />
    </VARIANT>
    <VARIANT name="TEST01022023">
      <PROGRAM name="99.884.0_M" />
      <PROGRAM name="99.884.0_MR" />
      <PROGRAM name="AAA_AAAAA" />
      <PROGRAM name="BBB_AAAAA" />
    </VARIANT>
  </REQUESTS>
</ROOT>

Send from Client to Server or the other way around.

<ROOT>
  <RESPONSE>
    <CURRENT name="TEST01022034">
      <PRODUCT name="Washing_machine_99.8854.0_99.8854.0" />
    </CURRENT>
   </RESPONSE>
</ROOT>

There are many small examples, 1000 variants. Is there a good working example for this use case? Thank you in advance for your help.

Windows Desktop App, WPF App or Windows Forms App. VS2017/2019

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Answer 1

Anonymous

Hi @Markus Freitag , Welcome to Q&A.

Regarding Socket, TcpClient and TcpListener, I have written a winforms related example.

Among them are about creating tcplistener and using tcpclient to connect.

Please refer to this link and post an update if you have any questions.

Best Regards, Jiale

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Markus Freitag 3,791

Please refer to this link and post an update if you have any questions.

Yes that looks good.

1_really_Good_1_

2_Close_Not_Work_is_Null_Dictionary_

There are important points missing, maybe you can help me.

Timeout during connection. I tried, without success. It does not wait 15 seconds. How can I solve this?

3__Error_NotConnection_NotWait_15000ms_

private void SendB_Click(object sender, EventArgs e)
{
	try
	{
		string txt = SendText.Text;
		byte[] buffer = Encoding.ASCII.GetBytes(txt);//ascii encoding
		socket.Send(buffer);
	}
	catch
	{
		Log("Not connected");
	}
}

I send a request, after 5 seconds there must be a response, otherwise error message. How can I solve this well?

<ROOT>
  <REQUESTS>
    <VARIANT name="TEST01022034">
      <PROGRAM name="87.1554.0_87.1554.0" />
    </VARIANT>
    <VARIANT name="TEST01022023">
      <PROGRAM name="99.884.0_M" />
      <PROGRAM name="99.884.0_MR" />
      <PROGRAM name="AAA_AAAAA" />
      <PROGRAM name="BBB_AAAAA" />
    </VARIANT>
  </REQUESTS>
</ROOT>

How can I check if the entire message <ROOT> </ROOT> was received. What is a good solution? Can I do it this way?

str += Encoding.ASCII.GetString(buffer, 0, length);
Log(socketSend.RemoteEndPoint.ToString() + "\n\t" + str);


int lengthFirstTag = str.IndexOf(">");
if (lengthFirstTag <= 0)
	continue;
string lastTag = "</" + str.Substring(1, lengthFirstTag);

if (str.IndexOf(lastTag) >= 0)
{
	Log(socketSend.RemoteEndPoint.ToString() + "\n\t   message ready, whole message received!");
}

enter image description here

private void SendB_Click(object sender, EventArgs e)
{
	try
	{
		EvTCP_NewMessageReceived.Reset();
		string txt = SendText.Text;
		byte[] buffer = Encoding.ASCII.GetBytes(txt);//ascii encoding
		socket.Send(buffer);

		//buffer = Encoding.ASCII.GetBytes(">");//ascii encoding
		//socket.Send(buffer);

	   
		if (!EvTCP_NewMessageReceived.WaitOne(15000))
		{
		  //  throw new Exception($"Customer class - no answer from request!");
		MessageBox.Show("Customer class - no answer from request!", "Info...", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
		}
	}
	catch
	{
		Log("Not connected SendB");
	}
}

protected AutoResetEvent EvTCP_NewMessageReceived; How can I simulate this? When do I have to take which event? Auto or Manual?

AutoResetEvent is only a pulse and is automatically reset? But why is there a reset function?

The most important points.

Connect, Timeout after 10 seconds and 5 attempts. Request -> no response, Timeout after 5 seconds error message

//socket.ReceiveTimeout = 3333;
//socket.SendTimeout = 3333;
//var result = socket.BeginConnect(iPEndPoint, null, null);
//bool success = result.AsyncWaitHandle.WaitOne(15000, true);
//if (success)

What would be the advantage/disadvantage of doing it via TcpClient, TcpListener Library? You have used the socket library.

I look forward to your help, your answers. Thanks.

The user interface should not be blocked by the socket interface. How can I achieve this?

Form1 - Client_cs.TXT

Form1 - Server_cs.TXT

Anonymous

2023-02-03T08:29:21.9833333+00:00

For socket connection timeout, check this link. Make a deeper research and modify the question.

Markus Freitag 3,791

Make a deeper research and modify the question.


//Create IP address and port number;
System.Net.IPAddress ip = IPAddress.Parse(Ipbox.Text);
int port = Convert.ToInt32(PortBox.Text);
IPEndPoint iPEndPoint = new IPEndPoint(ip, port);
//Determine whether you can connect to the server
try
{
	//socket.Connect(iPEndPoint);

	var result = socket.BeginConnect(iPEndPoint, null, null);
	bool success = result.AsyncWaitHandle.WaitOne(15000, true);
	if (success)
	{
		socket.EndConnect(result);
	}
	else
	{
		socket.Close();
		throw new SocketException(10060); // Connection timed out.
	}

Yes you are right, there were a lot of questions because the topic is complicated. I used the example from your link. If the server is not there, the client tries to connect, it does not wait 15 seconds, but immediately goes out with an exception. Maybe you have a solution for this point. Thank you in advance.

Markus Freitag 3,791 Reputation points

2023-02-06T11:48:42.1466667+00:00

Too bad you don't answer more. Your example is really good, the subtleties are missing. Maybe you can help me with the connection problem. Time-out. As I said would be very nice.

Once that is resolved I can close the thread. I check the other points and open a thread with only one point.

Anonymous

Sorry for late reply.

enter image description here

The following is the code about trying 15s connection, maybe it can help you, 15s error will occur on the unlistened ip.

Socket socket;//The socket responsible for the connection

private readonly ManualResetEvent TimeoutObject = new ManualResetEvent(false);
/// <summary>
/// Socket connection request
/// </summary>
///<param name="remoteEndPoint">Network endpoint</param>
///<param name="timeoutMSec">timeout</param>
public void Connect(IPEndPoint remoteEndPoint, int timeoutMSec)
{
    TimeoutObject.Reset();
    socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
    socket.BeginConnect(remoteEndPoint, CallBackMethod, socket);
    //block the current thread        
    if (TimeoutObject.WaitOne(timeoutMSec, false))
    {
        Log("Port is ok");
        Thread th = new Thread(receive);
        th.IsBackground = true;
        th.Start();
    }
    else
    {
        Log("timeout");
    }
}
//--asynchronous callback method   
private void CallBackMethod(IAsyncResult asyncresult)
{
    //Make a blocked thread continue      
    TimeoutObject.Set();
}

private void ConnectB_Click(object sender, EventArgs e)
{
    try
    {
        //Create IP address and port number;
        IPAddress ip = IPAddress.Parse(Ipbox.Text);
        int port = Convert.ToInt32(PortBox.Text);
        IPEndPoint iPEndPoint = new IPEndPoint(ip, port);
        Connect(iPEndPoint, 15000);
    }
    catch
    {
        socket = null;
        Log("Input error");
    }
}

Markus Freitag 3,791

Yes, thank you for answering after all.

First look looks good.

Unfortunately it does not work either. Timeout comes much too fast.

Test it with 125000ms. Then you see immediately that it does not work. Too bad, maybe you have a tip.

I don't know how the experts solve it. The problem is actually simple. Give the client 15, 30 or 60 seconds to connect.

not_Working_1_

public void Connect(IPEndPoint remoteEndPoint, int timeoutMSec)
{
	TimeoutObject.Reset();
	socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
	socket.BeginConnect(remoteEndPoint, CallBackMethod, socket);
	//block the current thread        
	if (TimeoutObject.WaitOne(timeoutMSec, false))
	//if (!TimeoutObject.WaitOne(timeoutMSec, false))    // ######
	{
		Log("Port is ok");
		Thread th = new Thread(receive);
		th.IsBackground = true;
		th.Start();
	}
	else
	{
		Log("timeout");
	}
}
//--asynchronous callback method   
private void CallBackMethod(IAsyncResult asyncresult)
{
	//Make a blocked thread continue      
	TimeoutObject.Set();
}

private void ConncectB_Click(object sender, EventArgs e)
{
	try
	{
		//Create IP address and port number;
		IPAddress ip = IPAddress.Parse(Ipbox.Text);
		int port = Convert.ToInt32(PortBox.Text);
		IPEndPoint iPEndPoint = new IPEndPoint(ip, port);
		Connect(iPEndPoint, 125000); // #####
	}
	catch
	{
		socket = null;
		Log("Input error");
	}

Second and third try. Nothing works as expected

TimeoutObject.Reset();
socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
var result = socket.BeginConnect(remoteEndPoint, CallBackMethod, socket);

WaitHandle wait = result.AsyncWaitHandle;

//block the current thread        
//if (TimeoutObject.WaitOne(timeoutMSec, false))
if (wait.WaitOne(timeoutMSec))
//if (!TimeoutObject.WaitOne(timeoutMSec, false))
{
	Log("Port is ok");
	Thread th = new Thread(receive);
	th.IsBackground = true;
	th.Start();
}
else
{
	Log("timeout");
}

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C# TcpClient/TcpListener / Full Duplex Communication / Sample

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