ObservableCollection does not update the DB

Oct 31, 2009 at 3:22 AM

this is the code I have for the class:

public class logFile : ObservableCollection<logLine>
    {
        public logFile(logConnDataContext dc) : base()
        {
              //blah blah collection initialization
        }
    }

    public class logLine : INotifyPropertyChanged
    {
        //just an example of one of the properties
        private DateTime _date;

        public DateTime Date
        {
            get { return _date; }
            set
            {
                _date = value;
                RaisePropertyChanged("Date");
            }
        }
        #region INotifyPropertyChanged Members
           // standard implementation of the interface
        #endregion
    }
in code i link to itemssource like this:
logDB = new logConnDataContext();
dataGrid1.ItemsSource = new logFile(logDB);
My question is:
when I do a logDB.SubmitChanges() the DB does not get updated! I can see in the debugger that the itemssource has the lines updated with the current values, but the db does not get updated!
any suggestions?