I have a DocumentTable and DocumentLineTable in a DataSet. They are linked by a FK relation on DocumentID, the primary key of the DocumentTable. I have a TexBox for DocumentDesc, bound to a docTableBindingSource, and a DataGridView bound to a docLineBindingSource. This docLineBindingSource has docTableBindingSource as its DataSource, and the FK_Relation as its DataMember.

When I insert a new Document, and add DocumentLines to the grid, try what I may, I cannot get the DocumentID foreign key in my child table to update to reflect the new DocumentID after updating the DocumentTable. What could I be doing wrong?