Loop Didn't Work Properly, 1 Row Only Update From Grid

Question

I make project in c# with access database, i want to update the data in 3 table in Ledger table it works fine but in Purchase table and Stock table for loop not work correctly loop repeat 1 row from grid and update it in tables, if in bill 3 rows it copy it 3 times.

 in this snap before update there is 4 rows data but data is not same as picture, when i update it save i think last row of grid repeatedly in tables.