BackgroundWorker still needs to call Invoke?

Question

In the last question Display progress bar while doing some work in C#?, people has recommend use of BackgroundWorker. I thought in BackgroundWorker DoWork method you can update the GUI directly, but why this function call need to be called using Invoke.

toolTip.SetToolTip(button, toolTipText);

Answer 1

The RunWorkerCompleted callback is marshalled onto the UI thread; DoWork is not.

You should use the ReportProgress method to update the UI during DoWork processing.

See: How to: Run an Operation in the Background