Gridview中的Update命令停止工作（以前工作和删除，选择工作正常）

I have a gridview that uses accessdatasource which has select, insert, delete and update. It used to work before perfectly but all of a sudden the update stopped working while the rest are still working as they supposed to be. I haven't changed anything in the gridview or datasource, but I added new fields to the table but are not displayed in gridview. I tested by deleting the new fields from the table which did not work either. Refreshed the datasoure and gridview as well. Here is the code I have a gridview that uses accessdatasource wh