How do I best write my own background-working and communicatible (sending progress updates and getting messages) non-visual class in C# 4?

Question

I have to develop a class which can run it's own hard-coded task in a background thread and communicate with container class sending him progress updates and taking messages from it. I believe I am going to extend BackgroundWorker class but it looks a bit weird to extend and I haven't managed to find a good example wit Google. Can you share a link to a good example of solving such a task? Please don't offer placing a BackgroundWorker visually on a form and reading the standard tutorial, it's not for my case. Maybe I'd better not extend but encapsulate a BackgroundWorker, but I hardly understand how to use it outide WinForms designer either :-(

Answer 1

You could do it as a Windows Service: http://www.c-sharpcorner.com/uploadfile/mahesh/window_service11262005045007am/window_service.aspx

Answer 2

BackgroundWorker will give you no obstacles to get the progress updates implemented, ReportProgress() is there to get that job done. "Sending messages" is another matter though.

You'll need a thread-safe queue in which you can stuff objects that represent a unit of work. Emptied by the BGW in its main loop in the DoWork event handler. .NET 4.0 certainly helps you do that, ConcurrentQueue gets you the queue.

Answer 3

I'd do it through a callback routine that reports status from the child thread and returns a value from the parent thread. In the following console app sample, I pass a string and return a bool but the arguments could be anything you'd like.

public delegate bool CallbackDelegate(string messageArg);

class Program
{
    static bool running = true;

    static void Main(string[] args)
    {
        for (int i = 0; i < 10; i++)
        {
            Worker worker = new Worker();
            worker.Callback = new CallbackDelegate(WorkerStatus);

            Thread thread = new Thread(new ThreadStart(worker.DoSomething));
            thread.IsBackground = true;
            thread.Start();
        }
        Console.ReadKey(); 
        running = false;
        Console.ReadKey();
    }

    static bool WorkerStatus(string statusArg)
    {
        Console.WriteLine(statusArg);
        return running;
    }
}

public class Worker
{
    public CallbackDelegate Callback { private get; set; }

    public void DoSomething()
    {
        bool keepGoing = true;
        while (keepGoing)
        {
            keepGoing = Callback("Thread ID: " + Thread.CurrentThread.ManagedThreadId.ToString() + " running");
            Thread.Sleep(new Random().Next(100, 2000));
        }
        Callback("Thread ID: " + Thread.CurrentThread.ManagedThreadId.ToString() + " done");
    }
}