databinding + INotifyPropertyChanged

Hi,

i have a class "user" that implements INotifyPropertyChanged.
with databinding i bind a objekt user1 to textboxes on a winform.

If i change the properties from user1, the textboxes will be updated.

Now i have a function that returns an objekt(user).
user1 = getuser(); -> no changes in the textbox.
with debugging i see, that the setter was not called.

How can i get this done ?
i want to see the returned data in my textboxes.

bye jo