title: datatable was nothing or null
body: <p>am trying to make a login system with permissions and i used SQL as a direct object with datagridview but i keep getting that the (dt) = nothing i took this video as a referencehttps ://www.youtube.com/watch?v=qjjEe00Pyr0&amp;ab_channel=ProgrammingforEverybody
  <a href="https://i.stack.imgur.com/nZwmX.png" rel="nofollow noreferrer">database image</a>but when i had an error i literally change my whole code the same as the video i tried to remove the dt.clear didn't work out and tried to fill the dt from sql still didn't work out am kinda stuck btw this is the first time posting in StackOverflow so if there is something i don't know about posting a q let me know <a href="https://i.stack.imgur.com/8mIvc.png" rel="nofollow noreferrer">code image </a></p>