I have 2 datatables within a dataset. One datatable (Table A)is filled with data completely from a data adapter.<BR><BR>The other table (Table B) is initially filled with a data adapter with the exception of 2 fields that I later want to fill with a values from Table A.<BR><BR>I am reading from Table A and am using the item_id to find the row that should match in Table B (i.e. the item_id is the PK of table B).<BR><BR> Dim i As Int16<BR> For i = 0 To .TableA.Count - 1<BR> Dim myrow As DataRow<BR> myrow = .TableB.FindByitem_id(.TableA.Item(i).item_id)<BR> myrow("myfield") =.TableA.Item(i).material(i).fieldtoinsert <BR>Next<BR><BR>I am getting the error "Object reference not set to an instance of an object". <BR><BR>I even tried just saying myrow("myfield")= "Test", but it won't seem to let me write to that field. <BR><BR>Any ideas on what I am doing wrong?