What would be the similarities and differences in DataGridview.Update() and Datagridview.Refresh() methods

What are the places to use DataGridview.Update() and Datagridview.Refresh()


I'm referring to datagridview1.update() and datagrdview1.refresh() methods calling after the data source is set , what would be the best sequence of calling above 2 methods, what is the correct way

datagridview1.DataSource = new List.......
datagridview1.Refresh();

or

datagridview1.DataSource = new List.......
datagridview1.Update();

or else when to use datagridview1.Update() or datagridview1.Refresh();

what is the underlying theory behind the Refresh and update methods calling , since it is bit confusing