Filter PowerApps gallery by Dynamics lookup value

Question

Sorry this seems such a basic question but I simply cannot find an equivalent example anywhere!

Given a new PowerApp created from the "start from data" template against the native D365 Contact entity. The new app contains a Gallery control. I simply want to filter it to only show Contacts that match a specific account ID.

I believed this should be as simple as this, but I cannot get this or any permutation that I've tried to work (syntax errors). Where am I going wrong? I've set the Items property of the control to this, but it's just not right. Among a couple of hours of guesses, I've tried appending ".id" or "_id" to parentaccountid (in various case permutations) I don't know where else to look.

Filter('Contacts', parentaccountid = "dd12fc2e-ab9a-4488-bc62-22e3bc048cb7")

Answer 1

I think you have to use Lookup property _accountid_value to accomplish this. Lookup property

Filter('Contacts', _accountid_value = GUID("dd12fc2e-ab9a-4488-bc62-22e3bc048cb7"))

Reference