how can something equal 0 without equaling 0 O.o

so i was trying to get the the room name off of a gui i made using treeviewitems and for some reason $selectedRoom == 0 and $selectedRoom <> 0. i dont get it please explain

$selectedRoom = GUICtrlRead(GUICtrlRead($TreeView1), 1)
ConsoleWrite($selectedRoom&@CRLF); returns room name, which is never == to 0
If $selectedRoom <> 0 Then
GUIDelete($Form1)
_joinRoom($selectedRoom)
EndIf

this should work but for some reason it tells me that the room name is <> to 0, but it fails to execute the code correctly

oh and since theres a huge no game policy im making the game thats why i needed this code.