BindingSource.ResetBindings()

I am developing an app with one function being tracking student attendance to classes my company teaches. I want to be able to add new students in a child-form, and then select the student in a combo-box column of the datagridview on the parent-form. On save of the child form I am using:

ActivityForm.AttendeeBindingSource.ResetBindings()

But it is not successfully updating the parent form with new attendees added. Any advice on how I can refresh the control on the parent-form would be much appreciated.