Backgroundworker and how to lock the shared object

[mihai a]

Hello C# Gurus,

My question is about threading in C# (backgroundwork er and shared object)

I have a communication class designed with singleton pattern (only one instance )

private PRS485 serial = PRS485.RS485;

Inside this class I’ve implemented a backgroundworke r for serial communication.
With the help of PData class I’ve created a shared object between the main thread and backgroundworke r thread. This object in my case is called data and passed as argument to the worker. After some racing problems I realized that I have to lock the shared object.
My problem: lock seems to have no effect. What I’m doing wrong here?
I’ve spend hours on Google searching for an answer. How do I implement the lock procedure correctly inside the backgroungworke r?

Please see below my code (simplified version)


Thank you for your time.


Mihai.

public sealed class PRS485
{
private static object locker = new object();
private PData data = new PData();
private SerialPort port;
private BackgroundWorker bgw;
private static readonly PRS485 rs485 = new PRS485();

private PRS485()
{
bgw = new BackgroundWorker();
bgw.WorkerReportsProgress = true;
bgw.WorkerSupportsCancellation = true;
bgw.DoWork += new DoWorkEventHandler(bgw_DoWork);
bgw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bgw_RunWorkerCompleted);
bgw.ProgressChanged += new ProgressChangedEventHandler(bgw_ProgressChanged);

}

public static PRS485 RS485
{
get { return rs485; }
}


public void ReadTelegrams(List<PTelegram> TelegramsToRead)
{
data.TelegramsToProcess = TelegramsToRead;
data.Step = 0;
data.ProcentProgress = 0;
data.Mode = false;
if (PortIsOpen && !bgw.IsBusy & data.TelegramsToProcess.Count>0)
{
bgw.RunWorkerAsync(data);
}
}


private void bgw_DoWork(object sender, DoWorkEventArgs e)
{
//backgroundworker thread !!
//here is my problem
//lock is not working
//tried also with lock(this) or lock(wData)
PData wData = e.Argument as PData;
lock(locker)
{
//modify wData object
}
e.Result = wData;
}

private void bgw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
PData rData = e.Result as PData;
//modify rData object
}
}

//now the Pdata class

public class PData
{
public List<byte> BBuffer = new List<byte>();
public List<PTelegram> TelegramsToProcess = new     List<PTelegram>();
public string Message=String.Empty;
public bool Mode = false;
public int CommunicationDelay = 100;
public int CommunicationTimeout = 1000;
public string MenuFunction = String.Empty;
public int ProcentProgress;
public int Step;
public byte Address = 0x00;
}