How to get the correct BindingContext position?

Hi
I am using 2 tables and have a datarelation between them as parent & child relation.

The child dataset displayed in a datagrid & because of the relation it displays only the rows belongs to the selected row in the parent table.

If I want to update any of the selected rows in the datagrid it does not accept the changes because the position of the BindingContext of the child dataset does not match the row getting updated.

The datagrid .CurrentRowIndex always starts from 0 to what ever displayed, everytime I change the parent row.

Is there a way to get the correct BindingContext .position of the child table for the selected row in the datagrid ?

Thanks for the help

I am having the same question in my mind right now! can someone tell us how to do this...please?