Change Visible of Datacard immediately

Hi Folks,

I'm new in PowerApps but in the past I edited my forms with InfoPath and everything was fine for me. 

Now we update to SarePoint online and we need to use PowerApps so here is my special question:

I need to toggle the visible of a Datacard based on the Value from a dropdown list. The special is, that the Values comes from a sharepoint list. So the normal way with 

visible = ThisItem.Vertragsart.value = "Lizenz"

is not working for me. I need the update immediately in the form. If I save the from than the DataCard is Visible or not but I have to make the DataCards visible or not but I need it immediately in the EditScreen.

I will add some Pics for better understanding 😉

Kind regards and thanks for hints and solutions.