c# - DataAdapter.Update() does not update data in DB -

i've got assignment requires me update northwind database, i've done tutorials follows

i fill datatable using dataadapter.fill(table).

i build delete,insert,update commands using commangbuilder

sqldataadapter adapter = new sqldataadapter(selectstr, conn); sqlcommandbuilder builder = new sqlcommandbuilder(adapter);  adapter.deletecommand = builder.getdeletecommand(true); adapter.updatecommand = builder.getupdatecommand(true); adapter.insertcommand = builder.getinsertcommand(true); adapter.fill(employees_table); 

i set primary key table:

datacolumn[] employees_keys = new datacolumn[2]; employees_keys[0] = employees.columns["employeeid"]; employees_table.primarykey = employees_keys;  

now i've attempted delete , add row:

// accepts employee object , creates new new row appropriate values  // employee table row  datarow row = convertemployeetorow(employeetoadd); employee_table.rows.add(row);` 

and deleting row:

datarow row = employees.rows.find(employeetodismiss.id); employees.rows.remove(row);  

i should point out i've attempted use row.setadded() , row.delete()

anyway, @ end when try update database

int k = employees_adapter.update(employees_table); 

on added rows k valued, on remove never, , in either case nothing gets updated @ in database itself.

any insight of i'm doing wrong?

make sure you're calling employees_adapter.acceptchanges() after call update() save changes database.