Using a Background Worker with a class

I haven't used a background worker before; all of the examples I've seen involve a single form. Can I use a background worker with an external class? (where the crunching is happening)
i.e.: I have a form that calls a routine in a class, and I would like to display a progress bar on the form with the progress of that routine. If anyone has a code sample that would be great.

Of course you can... just call the routine of the external class from within the BackgroundWorker's DoWork event.

Thanks for the reply. If I call the external routine from the main form in the DoWork routine, how do I use ReportProgress to get it's status?
For example, if the code is like this, how do I find out the progress of the DoSomeWork routine?

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
Dosomeworkclass dosomeworkclass = new Dosomeworkclass();
dosomeworkclass.Dosomework();
}

The examples I've seen have code like:
backgroundWorker1.ReportProgress(i, DateTime.Now);
but that code is in the form and not an external class.

There's no magic - the computer can't guess how much time your method will take to run. You need to report as-you-go from within the external method.
For example, if there's a for loop of 10 iterations in your method, you should probably call ReportProgress with the value i*10 in the i-th iteration.
Pass the BackgroundWorker as a constructor argument to "Dosomeworkclass", and call its ReportProgress method inside the "Dosomework" method in some way that makes sense.