Question

I am calling my background worker by the following code:

private void UpdateDataTimer_Tick(object sender, EventArgs e)
{
    if (!serialPortWorker.IsBusy)
    {
        serialPortWorker.RunWorkerAsync();
    }
}

My DoWork event is as follows:

private void serialPortWorker_DoWork(object sender, DoWorkEventArgs e)
{
    //Configures serial port
    connection.BaudRate = 19200;
    connection.DataReceived += new SerialDataReceivedEventHandler(DataReceivedEvent);

    //Sends the commands for opening diagnostics
    string[] init_commands = { "STRING", "STRING", "STRING", "STRING", "STRING" };
    foreach (string command in init_commands)
    {
        connection.WriteLine(command + connection.NewLine);
        Thread.Sleep(1000);
    }

    const string constant_message_section = "G03";
    string[] command_list = { "62", "64", "5C" };

    //Writes all commands to all radio addresses
    foreach (int address in radioAddresses)
    {
        foreach (string command in command_list)
        {
            for (int i = 0; i < MAX_ATTEMPTS; i++)
            {
                connection.WriteLine(constant_message_section + address.ToString("X4") + command);
                Thread.Sleep(500);
            }
        }
    }

    Thread.Sleep(1000); //Give a little time for all responses to come in
}

For some reason, after a few hundred calls of the UpdateDataTimer_Tick event, it will not run the serialPortWorker any more. I put a debugger at if (!serialPortWorker.IsBusy), and it indicated that the serialPortWorker is still busy. It must be hanging up somewhere in the DoWork event, right? Any ideas why?

For those that are interested, the data received event is as follows:

public void DataReceivedEvent(object sender, SerialDataReceivedEventArgs e)
{
    SerialPort sp = (SerialPort)sender;
    string receive = sp.ReadLine();

    try
    {
        Debug.Logger.WriteToDebug("Data Received Serial Port: " + receive);
    }
    catch { }

    try
    {
        int unit_address = Int32.Parse(receive.Substring(1, 4), System.Globalization.NumberStyles.HexNumber);

        if (radioAddresses.Contains(unit_address))
        {
            int radio_index = radioAddresses.IndexOf(unit_address) + 1;
            int max_index = radio_index * 3;

            integrityMonitor[radio_index] = DateTime.Now; //Last updated time

            int message_data = 0;

            if (receive.Contains("66"))
            {
                //Stuff
            }
            else if (receive.Contains("61"))
            {
                //Stuff
            }
            else if (receive.Contains("55"))
            {
                //Stuff
            }
        }
    }
    catch { }
}

Answer 1

Ok, since nobody has left an answer, I will. The issue was the line

connection.DataReceived += new SerialDataReceivedEventHandler(DataReceivedEvent);

being called during every tick of the timer in background worker. This would cause numerous instances of the event handler, which would eventually cause the background worker to lock up and report busy all the time. To correct this problem, I needed to put in

connection.DataReceived -= new SerialDataReceivedEventHandler(DataReceivedEvent);

in order to avoid having numerous event handlers processing the data received event. This has resolved my problem.