I recently startet .NET programming and tried to do a small network game.
The Connection is set up properly and messages get mostly written and read at normal behaviour. But at some random point on runtime, the reading stream doesn't recognize the incoming message.
The Connection is set up via Tcp listener and the corresponding stream.
//Get the network Stream
stream = client.GetStream();
w = new BinaryWriter(stream);
r = new BinaryReader(stream);
As I said before, the communication is working, but seems to freeze at a random time ingame at the following point:
//Waiting for enemy to attack
public int ready()
{
try
{
while (r.ReadString() != ClientMessages.ATTACK) { }
Thread.Sleep(20);
return r.Read();
}
catch (Exception ex)
{
MessageBox.Show("Error: " + ex.Message);
throw new Exception("Dead");
}
}
It's always the same, that it get stuck within the while-loop. The Binary Reader doesn't seem to notice any further client messages no matter how many times I send the "Attack" order.
But the program is not somewhere in no man's land... if I shut down the connection, the method throws its "connection lost exception" just as normal.
At first I thought that I had screwed up something in this method, but in the following example, where I do almost the same, everything's perfect (or at least seems to be.. got never stuck at this point)
//Waiting for feedback
public int waitforfeedback()
{
try
{
while (r.ReadString() != ClientMessages.HIT) { }
Thread.Sleep(10);
return r.Read();
}
catch (Exception ex)
{
MessageBox.Show("Error: " + ex.Message);
throw new Exception("Dead");
}
}
Is it possible, that the problem is caused by a backgroundworker (which I use to call the network methods)?
What should I do to handle this problem?
EDIT :
As requested, the Backgroundworker code:
private void waiting()
{
bw = new BackgroundWorker();
bw.DoWork += bw_DoWork;
bw.RunWorkerCompleted += bw_RunWorkerCompleted;
setter = true;
button.Content = "Waiting";
this.IsEnabled = false;
bw.RunWorkerAsync();
}
void bw_DoWork(object sender, DoWorkEventArgs e)
{
int hit = network.ready();
e.Result = hit;
}
Related
I am working on a program that receives data from a serial port and displays this on a GUI. I am very new to C# and this is a part of a project I am working on. I have tried to look for code for the past few weeks and watched every tutorial on this matter, all to fail. I am still very new to programming and OOP.
The issue I am having is that the received data is not being pasted in the display box. I have verified that the serial port works using Putty so that cannot be the issue.
Edit: Quick update, upon learning how to use the meter I am working with and closer inspection of the user manual, I discovered that I was able to connect to the meter using serialportname.open(). The issue was that I was not requesting data. For example, by writing "READ?" into the meter, a reading would be returned.
I see that you're not using the DataReceived event.
It could be an approach to what you're trying to achieve; it will trigger each time your serial port receives data, so you could use it to insert into the textbox1
private void serialPort1_DataReceived(object sender,SerialDataReceivedEventArgs e)
{
string Data= serialPort1.ReadLine();
displayToTxt(Data);
}
private void displayToTxt(string Data)
{
BeginInvoke(new EventHandler(delegate
{
textBox1.AppendText(Data);
}));
}
I used delegate to avoid thread errors.
first you need to add EventHandler
SerialPort1.DataReceived += new SerialDataReceivedEventHandler(ReceiveData);
then get data and update UI
public void ReceiveData(object sender, SerialDataReceivedEventArgs e)
{
System.Threading.Thread.Sleep(30);
SerialPort _SerialPort = (SerialPort)sender;
int _bytesToRead = _SerialPort.BytesToRead;
byte[] recvData = new byte[_bytesToRead];
_SerialPort.Read(recvData, 0, _bytesToRead);
this.BeginInvoke(new SetTextDeleg(UpdateUI), new object[] { recvData });
}
private void UpdateUI(byte[] data)
{
string str = BitConverter.ToString(data);
textBox1.Text += str;
}
I know this is old. But since it is still showing up in searches, I thought I would add my answer.
As mentioned in another answer, you need to assign a handler to the serial port.
public void OpenPorts()
{
foreach (string nm in SerialPort.GetPortNames())
{
SerialPort sp = new()
{
PortName = nm,
ReadBufferSize = 2048,
DiscardNull = true,
RtsEnable = true,
DtrEnable = true,
ReceivedBytesThreshold = 1
};
try
{
//This should throw an exception if the port is already open.
sp.Open();
sp.DataReceived += DataReceived;
//Make sure the buffer is empty
if (sp.BytesToRead != 0)
{
sp.DiscardInBuffer();
}
}
catch (Exception ex)
{
//Handle the exception here
}
}
public void DataReceived(object sender, SerialDataReceivedEventArgs e)
{
try
{
while ((sender as SerialPort).BytesToRead > 0)
{
SerialBuffer += (sender as SerialPort).ReadExisting();
}
(sender as SerialPort).DiscardInBuffer();
}
catch (InvalidOperationException ex)
{
_ = MessageBox.Show("exception thrown at DataReceived.", "Crashed", MessageBoxButton.OK, MessageBoxImage.Information);
}
}
Hello i created a program which reads serial data from a scoreboard, then depending on the string the program separates the data into different boxes on the form and then to different txt files.The purpose of this, is to use those txt files for livestreaming purposes in basketball games.
It's the first time i work with serial data and i am not a very experienced programmer.
My problem, as the title of this post suggests is that every now and then without any reason i am loosing some packages. This is happening randomly , for example in 10 second period i could 1 package while the next one none or 4.
private void ReadData()
{
Thread MyThread = null;
{
try
{
ThreadStart ThreadMethod = new ThreadStart(ReadFromPort);
MyThread = new Thread(ThreadMethod);
}
catch (Exception e)
{
Console.WriteLine("Failed to create thread! " + e.Message);
return;
}
try
{
MyThread.Start();
}
catch (Exception e)
{
Console.WriteLine("The thread failed to start! " + e.Message);
}
}
}
//Recieves data and write them on textbox (optionally on a txt)
private void ReadFromPort()
{
while (Receiver == true)
{
try
{
int count = ComPort.BytesToRead;
System.Windows.Forms.Application.DoEvents();
byte[] data = new byte[count];
ComPort.Read(data, 0, data.Length);
currentMessage = Combine(currentMessage, data);
ReceivedData = (BitConverter.ToString(data));
if (count > 0)
{
if (chBoxUpdate.Checked)
{
DataType = count;
tempData = ReceivedData;
this.Invoke(new EventHandler(DisplayText));
if (chboxTxt.Checked)
{
this.Invoke(new EventHandler(ExportData));
}
}
else if (chBoxPrevious.Checked)
{
DataType = count;
tempData = ReceivedData;
this.Invoke(new EventHandler(ClearData));
this.Invoke(new EventHandler(DisplayText));
if (chboxTxt.Checked)
{
this.Invoke(new EventHandler(ExportData));
}
}
}
}
catch (Exception e)
{
}
}
}
//Displays Text
private void DisplayText(object sender, EventArgs e)
{
string temp;
Console.WriteLine(tempData+ " (" + tempData.Length.ToString() + ")");
try
{
if (tempData.Length == 38)// && ReceivedData.Substring(12, 5) == "03-02")
{
if (tempData.Substring(12, 5) == "03-02")
{
DataText.AppendText(tempData.Substring(24, 8));
DataText.AppendText("\n");
Blink.Text = "Reading...";
timer1.Start();
timer1.Enabled = true;
}
}
else
if (tempData.Length == 35)
{
if (tempData.Substring(12, 5) == "45-02")
{
AttackTime.AppendText(tempData.Substring(24, 5));
Blink.Text = "Reading...";
AttackTime.AppendText("\n");
timer1.Start();
timer1.Enabled = true;
}
}
else
if (tempData.Length == 29)
{
if (tempData.Substring(12, 5) == "03-36")
{
HomeScore.AppendText(tempData.Substring(21, 2));
Blink.Text = "Reading...";
HomeScore.AppendText("\n");
timer1.Start();
timer1.Enabled = true;
}
else
if (tempData.Substring(12, 5) == "03-46")
{
AwayScore.AppendText(tempData.Substring(21, 2));
Blink.Text = "Reading...";
AwayScore.AppendText("\n");
timer1.Start();
timer1.Enabled = true;
}
}
}
catch (ArgumentOutOfRangeException)
{
}
}
Keep in mind that tempData and ReceivedData are the same here and as the programs appears now there's not any particular reason to set tempData=ReceivedData.This is a part of a different,older code i used in the begining which i never changed but it doesn't effect the program.
At first i am using a thread to enable the ReadFromPort then if the program finds that there are available data in line it displays them with the DisplayText and it's using the ExportData to export the data to a txt.I think the problem is somewhere there but as i am not very experienced i can't tell where.
Are there any suggestions on how to improve my code? If you more details or information i can provide them.
You are using Invoke, this blocks the caller thread until the event has been processed, and since you are updating the UI this can take some time. This probably causes some buffer to overflow and data to be discarded. So you should do as little work as possible on the reading thread.
There are a few alternatives
Put the data on a concurrentQueue, and let the UI thread have a timer that periodically triggers a method that reads from the queue and updates the UI.
Put the data on a concurrentQueue, wrapped in a blocking collection, have another background thread iterate over the blocking collection, using GetConsumingEnumerable, and post the result to the main thread once done. This would be suitable if there is significant processing to be done.
Use BeginInvoke to post the received data to the main-thread, this does not wait for the call to complete, but probably have slightly higher overhead that the previous alternatives. I would recommend not accessing any UI properties from the background thread, since by default no property of a UI class is threadsafe. Even if you might get away with it if you are only reading, I would not take the chance.
I'm creating a game in which I use TCP/IP connection. The problem is that I'm using .Invoke to help me receive and send message.
The program goes like this: I'm my first window, i'm starting and connecting to the server like this :
{
TcpListener listener = new TcpListener(IPAddress.Any, this.port);
listener.Start();
try {
this.client = listener.AcceptTcpClient();
gameWindow = new GameWindow(this.client, true);
gameWindow.StartGame();
}
}
then i'm connecting to it like this:
{
IPEndPoint ipEnd = new IPEndPoint(this.serverIP, this.port);
{
try {
client.Connect(ipEnd);
if (client.Connected) {
gameWindow = new GameWindow(this.client, false);
gameWindow.StartGame();
}
}
}
The constructor for gameWindow (which is a form) looks like this:
public GameWindow(TcpClient thisClient, bool isServer)
{
InitializeComponent();
this.client = thisClient;
this.reader = new StreamReader(thisClient.GetStream());
this.writer = new StreamWriter(thisClient.GetStream());
this.writer.AutoFlush = true;
}
I must wait for the server to send a message to the client, and then start the client ( I have a function .startGame() that uses .ShowDialog() and creates some pictureBoxs)
But nowhere I can get my handle created. I've tried to put this.createHandle() (read about it here) into GameWindow_Load but still not works. If I try to send a message with:
workerSendData.RunWorkerAsync(); I get:
Additional information: Invoke or BeginInvoke cannot be called on a control until the window handle has been created.
What can I do to get my handler created? Using Thread.Sleep will sleep my whole UI, which does not work (a "solution" found on the internet)
My code for sending message :
private void workerSendData_DoWork(object sender, DoWorkEventArgs e)
{
if (client.Connected) {
this.writer.WriteLine(this.toSend); // aici trimitem datele.
// de modificat : aici vom adauga in lista noastra miscarile.
this.Invoke(new MethodInvoker(delegate () { MessageBox.Show("Me:" + this.toSend + "\n"); }));
}
else {
MessageBox.Show("Send failed");
}
workerSendData.CancelAsync();
}
My code for receiving data:
private void workerReceiveData_DoWork(object sender, DoWorkEventArgs e)
{
while (client.Connected) {
try {
this.received = this.reader.ReadLine();
this.myTurn = true;
this.Invoke(new MethodInvoker(delegate () {
MessageBox.Show("This has been received: " + this.received);
/*this.tbReceive.AppendText("You:" + this.received + "\n");*/
}));
this.received = "";
}
catch (Exception x) {
MessageBox.Show(x.Message.ToString());
}
}
}
It seems that you cannot invoke an action before the Window is fully initialized and loaded. Assuming you are working in Windows Forms, there is a solution provided by #Greg D on this question, but it doesn't be to be the safest way to go.
I would suggest that you try to find a way to start the worker only after the window is loaded (for example using the Loaded event), so that the handle is definitely ready and this situation does not occur.
i do have an embedded board (mini/tiny 210)
and i did try building an application which uses system.socket and system.socket.net in C# ( vs2005 - wince5 device application but i do have wince 6 on my device!! )
my purpose is to send and receive data bytes using Ethernet. for sending , well there is no problem but receive does need multitasking.
i should start a task so it can listen to the port if there is any data upcoming but once i add thread part to my code the whole program crashes (dose not do that in pc x64 core i5) but in embedded board it will crash.
if i eliminate multi tasking i might lose some data when networkstream.read is not online or when networkstream.read is online and i'm waiting for data,which ends in program will not respond up until the timeout. here is some of my codes . hope it helps.
this code does work :
private void button_connect_Click(object sender, EventArgs e)
{
try
{
//Thread TH = new Thread(new ThreadStart(con));
//TH.Start();
con();
}
catch
{
MessageBox.Show("THREAD ERROR");
}
}
public void con()
{
try
{
cli = null;
cli = new TcpClient();
cli.Connect(IPAddress.Parse(textBox_ip.Text),Convert.ToInt32(textBox_port.Text));
st = null;
st = cli.GetStream();
button_connect.Enabled = false;
button_Close.Enabled = false;
button_disconnect.Enabled = true;
statusBar1.Text = "Connected to server";
//Thread rec = new Thread(new ThreadStart(recf));
//rec.Start();
}
catch
{
MessageBox.Show("Connection faild","Error");
statusBar1.Text = "Faild to connect to server";
}
this code dose not work :
private void button_connect_Click(object sender, EventArgs e)
{
try
{
Thread TH = new Thread(new ThreadStart(con));
TH.Start();
//con();
}
catch
{
MessageBox.Show("THREAD ERROR");
}
}
public void con()
{
try
{
cli = null;
cli = new TcpClient();
cli.Connect(IPAddress.Parse(textBox_ip.Text),Convert.ToInt32(textBox_port.Text));
st = null;
st = cli.GetStream();
button_connect.Enabled = false;
button_Close.Enabled = false;
button_disconnect.Enabled = true;
statusBar1.Text = "Connected to server";
//Thread rec = new Thread(new ThreadStart(recf));
//rec.Start();
}
catch
{
MessageBox.Show("Connection faild","Error");
statusBar1.Text = "Faild to connect to server";
}
}
as you can see i'm getting this crash while just one of my task is in the code the second task has been commented
i appreciate your help in advance
The crash is probably caused by updating UI elements from a secondary thread.
The con method reads a textbox and updates several buttons as well as a status bar, and this should only happen on the main application thread.
To verify whether this is the issue, you could simply comment out the lines in the con method that access UI elements (copy the textbox value to a member string before starting the thread, or just hard-code the IP address) and re-run the application.
Then to actually fix the problem you'll have to look into Control.Invoke.
I have created 2 programs. Both use timers with interval set to 250 milliseconds.
The problem is that my first program doesn't lock then I run it, and the second locks with out giving me ability to click stop button. By saying locks I mean that program runs do it's job until I stop it from VS.
I don't understand why I can't stop my first program while the basic same way work for other program. Any ideas?
Program that locks:
private void btnScan_Click(object sender, EventArgs e)
{
tmrInterval.Interval = (int)nudInterval.Value;
tmrInterval.Start();
}
private void ScanPort(IPAddress address, int port)
{
using (TcpClient client = new TcpClient())
{
IAsyncResult result = client.BeginConnect(address, port, null, null);
if (result.AsyncWaitHandle.WaitOne((int)nudTimeout.Value, false)) txtDisplay.AppendText("Port: " + port + " is open." + Environment.NewLine);
else txtDisplay.AppendText("Port: " + port + " is closed." + Environment.NewLine);
}
}
private void btnStop_Click(object sender, EventArgs e)
{
tmrInterval.Stop();
}
private void tmrInterval_Tick(object sender, EventArgs e)
{
ScanPort(IPAddress.Parse(txtIP.Text), currentPort);
currentPort++;
if (currentPort == nudTo.Value) tmrInterval.Stop();
}
Program that doesn't lock:
void tmrPingInterval_Tick(object sender, EventArgs e)
{
if (txtTo.Text == string.Empty) Ping(IPAddress.Parse(ip2str(startIP)));
else
{
if (currentIP >= endIP) tmrPingInterval.Stop();
Ping(IPAddress.Parse(ip2str(currentIP)));
currentIP++;
}
}
private void btnPing_Click(object sender, EventArgs e)
{
if (txtFrom.Text != string.Empty)
{
txtFrom.Enabled = false;
txtTo.Enabled = false;
txtDisplay.Text = string.Empty;
tsslPingCount.Text = string.Empty;
count = 0;
open = 0;
closed = 0;
tmrPingInterval.Interval = int.Parse(nudInterval.Value.ToString());
try
{
startIP = str2ip(txtFrom.Text);
if (txtTo.Text != string.Empty) endIP = str2ip(txtTo.Text);
currentIP = startIP;
tmrPingInterval.Start();
}
catch
{
MessageBox.Show("Input must be in IP format: 100.100.100.100", "Information", MessageBoxButtons.OK, MessageBoxIcon.Information);
txtFrom.Enabled = true;
txtTo.Enabled = true;
}
}
else MessageBox.Show("IP field cannot be empty!", "Information", MessageBoxButtons.OK, MessageBoxIcon.Information);
}
private void btnStop_Click(object sender, EventArgs e)
{
txtFrom.Enabled = true;
txtTo.Enabled = true;
tmrPingInterval.Stop();
}
private void Ping(IPAddress address)
{
Ping pingSender = new Ping();
PingOptions options = new PingOptions();
if (cbDontFragment.Checked) options.DontFragment = true;
else options.DontFragment = false;
string data = string.Empty;
int dataCounter = 0;
options.Ttl = (int)nudTTL.Value;
for (int i = 0; i < nudData.Value; i++)
{
dataCounter++;
if (dataCounter == 10) dataCounter = 0;
data += dataCounter.ToString();
}
byte[] buffer = Encoding.ASCII.GetBytes(data);
int timeout = 120;
try
{
PingReply reply = pingSender.Send(address, timeout, buffer, options);
if (reply.Status == IPStatus.Success)
{
}
else
{
}
}
catch (Exception ex)
{
txtDisplay.SelectedText += Environment.NewLine + ex.Message;
}
}
I'm going to make a guess here since we don't have enough information. I am guessing that tmrInterval in a System.Windows.Forms.Timer. If that is the case, the what's happening is that when the timer ticks, it is handed as a windows message (the same way that mouse clicks, keystrokes, and everything else that make your application appear 'not frozen' are handled).
In the first application, you are doing something that takes substantial time- opening a TCP port, then waiting for a (presumably) large number of milliseconds until the TCP connects or doesnt, then almost immediately doing it again the next time that the timer ticks. You are literally never giving the application a chance to respond to mouse clicks and keystrokes because the UI thread is busy trying to connect to some random ports somewhere.
In the second application, you are doing something relatively quick- just sending a ping somewhere. what you will probably see in the second application is that your application will 'stutter'- become unresponsive for just a second or less while it pings whatever other machine you pointed it at. It doesn't get hung because the UI thread isn't being given that much work to do.
To fix both of these, you should look into implementing a BackgroundWorker. Timers (of any sort) are not generally considered a good way to spawn background tasks in .NET.
About the first sample:
I guess from the context that the timer is a Windows.Forms.Timer. In the elapsed event you are executing a WaitOne(), and so effectively block the Messagepump.
As a possible solution, replace the Timer with a Threading.Timer to decouple the I/O from the main Thread.