Question

Is this possible?

What I want to do is have my doWork method instantiate another class and then call its start method. Then i would like to report progress from that class back to the ProgressChanged handler in the parent class. I’ve tried passing a reference to the BackgroundWorker but i get an error.

private void ComplianceWorker_DoWork(object sender, DoWorkEventArgs e)
    {
        ComplianceControlCenter CCC = 
         new ComplianceControlCenter(taskList.CheckedItems.OfType<string>().ToList(),
                                     file_box.Text, &ComplianceWorker);
        CCC.start();
    }

EDIT:

There is only 1 background worker. I would like to pass it by reference to the constructor of ComplianceControlCenter so i can send progress updates to it from inside that class. The reasoning is the class do some fairly complicated work and i need to have a division. So again, i would like to pass the background worker from the doWork method to the CCC object so i can call ComplianceWorker.ReportProgress();

Error 1 Cannot take the address of, get the size of, or declare a pointer to a managed type (‘System.ComponentModel.BackgroundWorker’)

Answer 1

You could do that, although I don’t see what purpose it would serve for simple cases. Since you are already inside the business method of a BackgroundWorker there’s no point in using yet more threads by creating another BackgroundWorker and you could do the same work inline.

If you still want to have a second BackgroundWorker, you can propagate progress changed events from the second worker to the first by attaching a handler to the second worker’s ProgressChanged event. This handler would then raise the ProgressChanged event on the first worker, propagating the news.

For example:

private void ComplianceWorker_DoWork(object sender, DoWorkEventArgs e)
{
    var CCC = new ComplianceControlCenter(/* ... */);

    // Assume that CCC exposes a BackgroundWorker, but read below
    var worker = CCC.Worker; // "second" worker
    worker.ProgressChanged += this.PropagateProgressChanged;

    CCC.start();
}

private void PropagateProgressChanged(object sender, ProgressChangedEventArgs e)
{
    var worker = this.worker; // "first" worker
    worker.ReportProgress(e.ProgressPercentage, e.UserState);
}

This code attaches an event handler to the “second” worker with

var worker = CCC.Worker; // "second" worker
worker.ProgressChanged += this.PropagateProgressChanged;

which assumes that ComplianceControlCenter exposes its own BackgroundWorker directly. Since that may not be the case, you can turn the relationship around by passing a reference to this.PropagateProgressChanged to the constructor instead and letting it attach the event handler for you.