Refreshing source of AutoComplete for each row according to previous data in DGV

Hi

I have a DGV bounded to a DataTable and users can populate rows in DGV with AutoComplete mode. All that I want to do is, refreshing the source of AutoComplete for each new row according to my base table (TableB) and also previous data that user entered in same column before current row in DGV (in TableA).

DGV.DataSource is TableA
AutoComplete.DataSource is TableB

I can do this job easily in MS Access but i don't know any thing about use existing relationship in DataSet with instance of DataTables. actually my problem solved if i can use relationships between filled DataTables.

Any help will be greatly appreciated.