Category: Problem Solutions

Can’t Select Records in Polymorphic Lookup? Here’s the Fix!

Polymorphic lookups (like Regarding in Dynamics 365) are great—until you can’t pick records from your custom table or even system tables like Users. Frustrating, right? Here’s a quick checklist to get you back on track:

1. Check Custom JavaScript 🚫

Custom JS might be blocking your lookup. Disable any scripts on the form and test again.

2. Confirm Table is in Your Model-Driven App ✅

Open your app in the Modern App Designer (with Admin access). Is your missing table listed under Tables? If not, add it!

3. Use Classic Designer if Needed 🕰️

If the modern designer won’t let you add that table, switch to the Classic App Designer and add it there.

Quick Recap

  • Polymorphic lookup dropdown depends on your app’s table list.
  • Custom JS can interfere—check first.
  • Missing tables? Add them using the app designer.

Power Apps: Exception in Canvas Apps – Object not set to an instance of an object.

Hey there,

Recently, I have encountered the following exception in my Power Apps – Canvas App.

The requested operation is invalid.
Server response: [Datasource name] failed: An error has occurred. Object not set to an instance of an object.
ClientRequestedId: [#GUID]

Canvas App

If you are also facing this exception in your Canvas Apps, then the following proposed solution is for you.

Exception:

Actually, you are facing this exception because you are passing a “null” value to your Canvas App “function” (Filter/LookUp/Search etc.). All you need to do is to check your value before calling a function.

Solution:

To avoid this exception, just make sure you are writing your expressions in a correct way.

Correct:
If(
(!IsBlank(<‘Control Name’>)),
Filter(<‘Datasource name’>, <‘Column name’> = <‘Control Name’>.Text)
)

Incorrect:
Filter(<‘Datasource name’>, <‘Column name’> = <‘Control Name’>.Text)

  1. You should use this approach with all such expressions in your Canvas App.
  2. “<‘Control name’>” inside “IsBlank” method can be replaced with your variable name, if you are using variable for filtration.
  3. Similarly, “Filter” function can be replaced with LookUp, Search, or similar functions, it depends from where you are getting that above error.

I hope it’ll help you.

Thank you!