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C# UDP Socket.ReceiveFrom() breaks loop without exeption

I'm trying to make a game using sockets and UDP, i made a server class where when i call the start method i run a task with a loop to receive packets and process them, i used Socket.ReceiveFrom(packet, ref sender); inside a try catch block with everything inside a while loop, first i forgot to add Socket.Bind(new IPEndPoint(IPAddress.Parse("127.0.0.1"), 25000)); so i got a loop of bind exeptions which is normal but now that i added this line my program is freaking out see the code bellow
public class UDPServer
{
public UDPServer()
{
Socket = new Socket(AddressFamily.InterNetwork ,SocketType.Dgram,ProtocolType.Udp);
Socket.Bind(new IPEndPoint(IPAddress.Parse("127.0.0.1"), 25000));
}
public void Start()
{
IsBound = true;
try
{
Task.Run(NetworkLoop);
}
catch (Exception e)
{
throw e;
}
}
private void NetworkLoop()
{
EndPoint sender = new IPEndPoint(IPAddress.Any, 0);
byte[] packet = new byte[1];
int dataSize = 0;
while (IsBound)
{
try
{
dataSize = Socket.ReceiveFrom(packet, ref sender);
Console.WriteLine(sender.ToString() + " with " + packet.Length + " of " + dataSize);
}
catch (Exception e)
{
Console.WriteLine("Reading exeption : " + e.Message);
}
}
}
}
I debugged this and it seems that now when going step by step to the line
dataSize = Socket.ReceiveFrom(packet, ref sender); it just both exit the try catch block without any exeption catched AND breaks the while loop...
Is this normal behaviour ??

Your UDPServer.Start() method is not blocking, because Task.Run will run asynchronously.
Task.Run(NetworkLoop); // This is non-blocking
Your UDP server will work by either:
Task.Run(NetworkLoop).Wait(); // This is blocking
or
new UDPServer().Start();
Console.WriteLine("Press <enter> key to stop UDP server...");
Console.ReadLine(); // This block until user hit <enter> key

TcpClient hangs

I am working on a simple Client to send data to a server at my office. I tested the code locally on my computer using a server called TCPServer, I connect, send data, receive reply, disconnect, send again, rinse and repeat, it all works perfectly, but when I connect to office and do the same thing it connects fine, I can connect/disconnect forever, but when I send data it just hangs. Nothing is received in the log at the office. I can't send a single byte there.
Seems like a firewall issue doesn't it.
But I can run an older program I wrote years ago in Delphi (pascal), and it connects and sends the same data over without issue, same port, everything, so the problem is not a firewall issue. Thoughts on this? Here is the basic code layout.
Connect Button
Disconnect Button
Send Button
At the top of the class I declare the TcpClient Variable
public TcpClient m_client = new TcpClient();
In the _Click for Connect Button and Disconnect Button I have code to connect to server and set some indicators etc
private void ConnectButton_Click(object sender, EventArgs e)
{
string address = FixIP(IPAddressMaskedTextBox.Text);
int Port = Convert.ToInt32(PortNumberMaskedTextBox.Text);
Control control = (Control)sender;
String name = control.Name;
try
{
switch (name)
{
case ("ConnectButton"):
//Connect to server
connect(address, Port);
if (m_client.Connected)
{
SingleConnectionRichTextBox.Clear();
ConnectedLightButton.BackColor = Color.Lime;
SingleConnectionRichTextBox.Text += "Connected at IP " + address + " and Port " + Port.ToString() + "\r\n";
}
break;
case ("DisconnectButton"):
if (m_client.Connected)
{
SingleConnectionRichTextBox.Text += "Connection Terminated\r\n";
ConnectedLightButton.BackColor = Color.Red;
m_client.Client.Disconnect(false);
m_client = new TcpClient();
}
break;
}
}
catch (Exception err)
{
MessageBox.Show(err.ToString());
}
}
public void connect(string address, int port)
{
try
{
if (!m_client.Connected)
{
ConnectedLightButton.BackColor = Color.Yellow;
SingleConnectionRichTextBox.Text += "Attempting to Connect...\r\n";
m_client.Connect(address, port);
}
else
{
SingleConnectionRichTextBox.Text += "Connection Failed...\r\n";
ConnectedLightButton.BackColor = Color.Red;
throw new Exception("Connect: Already connected\r\n");
}
}
catch (Exception err)
{
MessageBox.Show(err.ToString());
}
}
The Send button has it's own event, mostly because when connecting to office it can take a minute for sockets to be created etc.
private void SendButton_Click(object sender, EventArgs e)
{
try
{
if (m_client.Connected)
{
string completeString = "";
for (int cnt = 0; cnt < SingleSendRichTextBox.Lines.Count() - 1; cnt++)
{
string aLine = Regex.Replace(SingleSendRichTextBox.Lines[cnt], #"\e\[(\d+;)*(\d+)?[ABCDHJKfmsu]", "");
if (cnt == 0)
{
//First line gets Start Block, plus a CR on end
aLine = (char)0x0B + aLine + (char)0x0D;
}
else if (cnt == (SingleSendRichTextBox.Lines.Count() -1))
{
//Last line gets CR + End Block + CR on end
aLine += (char)0x0D + (char)0x1C + (char)0x0D;
}
else
{
//All middle lines get CR on end
aLine += (char)0x0D;
}
//MessageBox.Show("Sending line# " + cnt.ToString() + " = " + aLine);
completeString += aLine;
}
Byte[] data = Encoding.ASCII.GetBytes(completeString);
WriteBytes(data);
ReadAllBytes();
}
else
{
MessageBox.Show("Nothing is connected currently...");
}
}
catch (Exception err)
{
MessageBox.Show(err.ToString());
}
}
public void WriteBytes(Byte[] data)
{
try
{
if ((m_client.Connected)&&(data.Count() > 0))
{
// Get access to network stream
NetworkStream stm = m_client.GetStream();
stm.Write(data, 0, data.Length);
stm.Flush();
//MessageBox.Show("Data Sent, length = " + data.Length.ToString());
}
else
{
MessageBox.Show("Either we are not connected, or there is no data to send!!");
}
}
catch (Exception err)
{
MessageBox.Show(err.ToString());
}
}
public void ReadAllBytes()
{
try
{
// Buffer to store the response bytes.
Byte[] readdata = new Byte[256];
// String to store the response ASCII representation.
String responseData = String.Empty;
NetworkStream stm = m_client.GetStream();
// Read the first batch of the TcpServer response bytes.
Int32 bytes = stm.Read(readdata, 0, readdata.Length);
responseData = Encoding.ASCII.GetString(readdata, 0, bytes);
SingleReplyRichTextBox.Text += responseData + "\r\n";
}
catch (Exception err)
{
MessageBox.Show(err.ToString());
}
}
Does anything in here raise a red flag that is obvious? I tried Stream VS NetworkStream. I tried turning off the Reply listener. I took this code and combined it all into one function, and moved the TcpClient creation over to a different Class as static so I could create it in each function, but while all of these worked fine locally, nothing works connecting to office. It won't send a single byte. I set m_client as static at the top too, works fine locally, not to office.
Is GetStream failing maybe? or its sending the data on a different socket?

use a Task and cancellation token to cancel the task. Don't init a "new" TCPclient. In the background the TCPclient will be not closed (socket-timeout of .net)
Use try catches to see the exception and add the log to the conversation to make it more clear pls

Exception after reset serial connection to a different Baud rate

In my application I'm using a 9600 baud rate serial connection and I want to use a 115200 baud rate connection for data transfer.
I've disconnected from the old connection and set it to be null value, and set my serial connection to new connection with different baud rate.
The connection is unstable and I sometimes get a System.ObjectDisposedException - what did I miss?
The connection code
public string startConnection()
{
if (serial != null)
{
serial.Dispose();
}
foreach (string portname in SerialPort.GetPortNames())
{
serial = new SerialPort(portname, 9600, Parity.None, 8, StopBits.One);
serial.ReadTimeout = 5000;
serial.WriteTimeout = 5000;
serial.Handshake = System.IO.Ports.Handshake.None;
serial.NewLine = "\n";
string received = "";
try
{
serial.Open();
serial.DiscardInBuffer();
serial.Write(":09;BATTERY;");
Thread.Sleep(500);
received = serial.ReadLine();
if (received.Contains(";BATTERY;V="))
{
status = SERIAL_CONNECTED;
return portname;
}
}
catch (Exception err)
{
try
{
serial.Close();
status = DISCONNECTED;
}
catch (Exception)
{
// throw;
}
}
}
throw new Exception("couldn't connect to coms");
//return "couldn't connect to coms";
//this.Close();
}
Disconnect function:
public void disconnect ()
{
if (serial == null || serial.IsOpen==false ||status == DISCONNECTED)
return;
status = DISCONNECTED;
serial.Close();
serial = null;
}
The main program is:
private async void BurnOFP_click(object sender, RoutedEventArgs e)
{
startConnection();
some actions.............
disconnect();
var t = new Task(() =>
{
try
{
myUswm.startModemConnection(); // same but with different baud rate
}
catch (Exception e2) { MessageBox.Show(e2.Message); }
});
t.Start();
t.Wait();
modem = new XMODEM_FullDotNET(myUswm.getSerialPort(), XMODEM_FullDotNET.Variants.XModemCRC);
buff = File.ReadAllBytes(softwareFilePath_Text.Text);
if (buff.Length < 1)
{
MessageBox.Show("ERROR : wrong OFP file");
return;
}
if (myUswm.prepareOFPBurning()) // sends u to start transfer
{
if (isBurning == false)
{
isBurning = true;
modem._ProgressSent = 0;
myProgBar = new myProgressBar(modem);
myProgBar.StartTransfer(modem, buff.Length);
myProgBar.Show(); // show window
// got the Exception here!!!!!!!!!!
var t3 = new Task(() =>
{
modem.Send(buff);
});
............
}
else
MessageBox.Show("burning in progress..");
}
}
catch (Exception e1)
{
MessageBox.Show(e1.Message);
}
}
Thanks for any help

RESOLVED
my problem was A bad timing caused by closing and reopen the same port.
I've found the information in MSDN Serial class:
The best practice for any application is to wait for some amount of time after calling the Close method before attempting to call the Open method, as the port may not be closed instantly.
my solution was keeping the connection alive and change the baud rate and update the connection status in my application manually.

Foreach freezing form

I know there are plenty of things about foreach freezing forms but I can't find a solution to my problem. I already have the server portion of this program working I am trying to make a client side that while connecting to the server this code will be preformed txtConn.AppendText("Attempting connection.");
This is the code that I have for the socket connection
private static Socket ConnectSocket(string server, int port, RichTextBox txtConn, BackgroundWorker backgroundWorker1)
{
Socket s = null;
IPHostEntry hostEntry = null;
// Get host related information.
hostEntry = Dns.GetHostEntry(server);
// Loop through the AddressList to obtain the supported AddressFamily. This is to avoid
// an exception that occurs when the host IP Address is not compatible with the address family
// (typical in the IPv6 case).
backgroundWorker1.RunWorkerAsync();
foreach (IPAddress address in hostEntry.AddressList)
{
IPEndPoint ipe = new IPEndPoint(address, port);
Socket tempSocket =
new Socket(address.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
Console.WriteLine(ipe);
try
{
attempt++;
txtConn.Select(txtConn.TextLength, 0);
txtConn.SelectionColor = Color.Aqua;
if (attempt == 1)
{
txtConn.AppendText("Attempting connection.");
}
else if (attempt > 1)
{
txtConn.AppendText("\r" + "Attempting connection.");
}
txtConn.SelectionColor = txtConn.ForeColor;
tempSocket.Connect(ipe);
}
catch (ArgumentNullException ane)
{
Console.WriteLine("ArgumentNullException : {0}", ane.ToString());
txtConn.Select(txtConn.TextLength, 0);
txtConn.SelectionColor = Color.Red;
txtConn.AppendText("\r\n" + "Connection could not be established.");
txtConn.SelectionColor = txtConn.ForeColor;
}
catch (SocketException se)
{
Console.WriteLine("SocketException : {0}", se.ToString());
txtConn.Select(txtConn.TextLength, 0);
txtConn.SelectionColor = Color.Red;
txtConn.AppendText("\r\n" + "Connection could not be established.");
txtConn.SelectionColor = txtConn.ForeColor;
}
catch (Exception e)
{
Console.WriteLine("Unexpected exception : {0}", e.ToString());
txtConn.Select(txtConn.TextLength, 0);
txtConn.SelectionColor = Color.Red;
txtConn.AppendText("\r\n" + "Connection could not be established.");
txtConn.SelectionColor = txtConn.ForeColor;
}
if (tempSocket.Connected)
{
Console.WriteLine("Connected");
s = tempSocket;
break;
}
else
{
continue;
}
}
return s;
}
My program looks like this
When I run the program and connect with say the wrong Port, it checks all the possible ips on my computer and waits till after the foreach statement to display errors or anything. How can I make it actively display this?This is when it runs

You need to run your code in a different thread so that the UI can still update while it is executing.
The easiest way to do this is by adding the connection loop to a new task in the ThreadPool.
ThreadPool.QueueUserWorkItem(i => {
// Connection loop goes here.
});
If you need other options you can also use a Task, BackgroundWorker, etc.

I just answered a similar question here, but to expand on it for your particular case, it looks like you aren't actually using backgroundWorker1. The foreach should be done in a method referenced by the backgroundWorker1.DoWork event. You'll also need to create a method for the backgroundWorker1.ProgressChanged event. You can use ReportProgress to pass a string and then append that message to your textbox:
From your foreach loop in the Worker_DoWork method, you will report progress instead of updating the RichTextBox directly:
worker.ReportProgress(0, "Connection could not be established.");
And then in the Worker_ProgressChanged method, you will use something like this to update the RichTextBox:
txtConn.AppendText(e.UserState.ToString());

Use should use Async methods from Socket class or run this stuff in another thread. You can use BackgroundWorker to do that as well.

Winforms background worker gets stuck

I am trying to build a simple code that joins csv files into one distinct file, but my background worker seems to have a mind of its own and my code gets stuck every time.
Here is my code for joining the file using the background worker:
private void backgroundWorker_DoWork(object sender, DoWorkEventArgs e)
{
try
{
if (string.IsNullOrEmpty(saveFilePath))
{
this.Invoke(new MethodInvoker(delegate
{
btnBrowseSave.PerformClick();
}));
}
if (!string.IsNullOrEmpty(saveFilePath))
{
if (dragEventArgs != null)
files = (string[])dragEventArgs.Data.GetData(DataFormats.FileDrop);
int filesCount = 0, rowsCount = 0;
foreach (string file in files)
{
filesCount++;
int fileTotalLines = File.ReadAllLines(file).Length;
this.Invoke(new MethodInvoker(delegate
{
lblFileName.Text = "Loading file: " + file.Substring(file.LastIndexOf("\\") + 1);
lblTotalFiles.Text = "File " + filesCount + " of " + files.Length;
}));
using (StreamReader reader = new StreamReader(file))
{
using (StreamWriter writer = new StreamWriter(saveFilePath))
{
while (!reader.EndOfStream)
{
try
{
while (stopPosition > rowsCount)
{
reader.ReadLine();
rowsCount++;
}
string email = reader.ReadLine().Trim();
if (!string.IsNullOrEmpty(email) && !dicEmails.ContainsKey(email))
{
dicEmails.Add(email, null);
writer.WriteLine(email);
}
rowsCount++;
stopPosition++;
backgroundWorker.ReportProgress((rowsCount * 100 / fileTotalLines), (int)ProgressType.Row);
if (backgroundWorker.CancellationPending)
return;
}
catch (Exception ex)
{
hadReadErrors = true;
}
}
}
}
backgroundWorker.ReportProgress(0, (int)ProgressType.Row);
backgroundWorker.ReportProgress((filesCount * 100 / files.Length), (int)ProgressType.File);
}
}
}
catch (Exception ex)
{
hadReadErrors = true;
MessageBox.Show(ex.Message);
}
finally
{
backgroundWorker.Dispose();
}
}
private void backgroundWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
try
{
switch ((int)e.UserState)
{
case (int)ProgressType.Row:
lblFileProgress.Text = e.ProgressPercentage + "%";
fileProgressBar.Value = e.ProgressPercentage;
break;
case (int)ProgressType.File:
lblTotalProgress.Text = e.ProgressPercentage + "%";
totalProgressBar.Value = e.ProgressPercentage;
break;
}
}
catch (Exception ex) { }
}
When I run in debug mode and go with the debugger I don't see any problems, but when I let the code run it self it gets stuck and crashes.
Can someone PLEASE help me and tell me what am I missing out here ?
Here is the exception:
Managed Debugging Assistant 'ContextSwitchDeadlock' has detected a problem in
'C:\Users\Develop\Desktop\ExcelBuilder\ExcelBuilder\bin\Debug\ExcelBuilder.vshost.exe'.
Additional information: The CLR has been unable to transition from COM context 0x90fb78
to COM context 0x90fc30 for 60 seconds. The thread that owns the destination
context/apartment is most likely either doing a non pumping wait or processing a very
long running operation without pumping Windows messages. This situation generally has
a negative performance impact and may even lead to the application becoming non
responsive or memory usage accumulating continually over time. To avoid this problem,
all single threaded apartment (STA) threads should use pumping wait primitives
(such as CoWaitForMultipleHandles) and routinely pump messages during long running operations.

I did a small example of your program, trying to guess what it must do (https://github.com/anderson-rancan/stackoverflow_28798348, drag and drop 4 files to the groupbox, lorem?.csv), and there is a few things that you should consider:
never try/catch a unknown exception, every exception or something you cannot deal with (https://msdn.microsoft.com/en-us/library/ms182137.aspx)
when using a BackgroundWorker on a form, use the "sender" for references to it, it's a thread safe object to your method (https://msdn.microsoft.com/en-us/library/cc221403(v=vs.95).aspx)
maybe you are updating too fast your form, change your Invoke method to BeingInvoke, and do the update async (https://msdn.microsoft.com/en-us/library/0b1bf3y3(v=vs.110).aspx)
So, just fixing that was possible to run it, like this:
private void backgroundWorker_DoWork(object sender, DoWorkEventArgs e)
{
BackgroundWorker bckw = (BackgroundWorker)sender; // Recommended way, thread safe
try
{
if (string.IsNullOrEmpty(saveFilePath))
{
this.Invoke(new MethodInvoker(delegate
{
btnBrowseSave.PerformClick();
}));
}
if (!string.IsNullOrEmpty(saveFilePath))
{
if (dragEventArgs != null)
files = (string[])dragEventArgs.Data.GetData(DataFormats.FileDrop);
int filesCount = 0, rowsCount = 0;
foreach (string file in files)
{
filesCount++;
double fileTotalLines = File.ReadAllLines(file).Length;
this.BeginInvoke(new MethodInvoker(delegate
{
lblFileName.Text = "Loading file: " + file.Substring(file.LastIndexOf("\\") + 1);
lblTotalFiles.Text = "File " + filesCount + " of " + files.Length;
})); // Invoke async, way too fast this...
using (StreamReader reader = new StreamReader(file))
{
using (StreamWriter writer = new StreamWriter(saveFilePath))
{
while (!reader.EndOfStream)
{
try
{
while (stopPosition > rowsCount)
{
reader.ReadLine();
rowsCount++;
} // why are you using that? it won't get TRUE
string email = reader.ReadLine().Trim();
if (!string.IsNullOrEmpty(email) && !dicEmails.ContainsKey(email))
{
dicEmails.Add(email, null);
writer.WriteLine(email);
}
rowsCount++;
stopPosition++;
bckw.ReportProgress((int)Math.Round(rowsCount * 100 / fileTotalLines, 0), (int)ProgressType.Row);
if (bckw.CancellationPending)
return;
}
catch (Exception ex)
{
hadReadErrors = true;
throw; // Throw it again, or you won't know the Exception
}
}
}
}
bckw.ReportProgress(0, (int)ProgressType.Row);
bckw.ReportProgress((filesCount * 100 / files.Length), (int)ProgressType.File);
}
}
}
catch (Exception ex)
{
hadReadErrors = true;
MessageBox.Show(ex.Message);
}
finally
{
bckw.Dispose();
}
}
private void backgroundWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
//try
//{
switch ((int)e.UserState)
{
case (int)ProgressType.Row:
lblFileProgress.Text = e.ProgressPercentage + "%";
if (e.ProgressPercentage <= fileProgressBar.Maximum)
fileProgressBar.Value = e.ProgressPercentage;
break;
case (int)ProgressType.File:
lblTotalProgress.Text = e.ProgressPercentage + "%";
totalProgressBar.Value = e.ProgressPercentage;
break;
}
//}
//catch (Exception ex) { } // Don't catch everything
}
Finally, may I suggest another approach?
You're reading the file two times: one to get the number of lines, and another to read each line. Try to do this just once, you'll get a better result.