wpf Converter with Combobox

wpf Converter with Combobox

lets say i have a class address
public partial class Address
{
public int Id { get; set; }
public Nullable<int> CountryId { get; set; }
public Nullable<int> CityId { get; set; }
public string Details { get; set; }
public Nullable<bool> IsDefault { get; set; }
public Nullable<int> PersonId { get; set; }
}
i want to know how can i use converter with a combobox inside the grid to
show cities in that combobox based on selected country in another combobox
inside the grid. i need to now the syntax how can i use the countryID to
pass it to converter to get list of cities and binding it to CityCombobox
in datagrid and on changing the Country this list is updated according to
the selected country.. Thanks