How to refresh Bindingsource?

Question

When I a do some changes in my table in database, and I want refresh bindingsource I use this code:

 housemateBindingSource.DataSource = from h in dc.Housemates
                                     select h;

This work. But for me most useful is this code:

 housemateBindingSource.DataSource = dc.Housemates;

 but it dosen't work. I don't know why. Enobody help me?