OnAskForProgressReport - BackgroundWorker

[rliq]

I have been using BackgroundWorker components recently. I have a long process and through OnReportProgress, every now and again it lets my foreground thread (Form) know how it's doing...

In some scenarios though, my User may get impatient and demand the BackgroundWorker tell them how it is doing right that moment. They want a [Tell Me!] button.

Assuming I have a component defined as follows:

public class BackgroundMoveFinder : BackgroundWorker
{
    //
}

What techniques are there for communicating from the foreground thread to the background worker?

Is this good? What other options are there?

public class BackgroundMoveFinder : BackgroundWorker
{
    private Boolean _sendProgress = false;

    public void TellMe()
    {
        lock (_sendProgress )
        {
            _sendProgress = true;
        }
    }

    // then regularly in my RunWorkerAsync...

    Boolean fireEvent = false;

    lock (_sendProgress )
    {
        if (_sendProgress )
        {
            _sendProgress = false;
            fireEvent = true;
        }
    }

    if (fireEvent)
        OnReportProgress(....);

    ...
}

// then call, from the foreground thread
myMoveFinder.TellMe();

Also, I'm not 100% sure if that's the best way to lock or even whether locking is required in this case?