topic Re: Unhandled Exception when using InputListBox in Inventor Programming Forum

Unhandled Exception when using InputListBox

steinarr34755 — Fri, 14 Aug 2026 11:07:43 GMT

When using InputListBox in iLogic I get an Unhandled exception:

This happens after the user chooses from the list box, pressing continue allows the script to keep going and the users choice does get passed on correctly so the script still works, apart from the above pop up.

This happens on Inventor 2026.2 And, at least on my machine, happens when I run the InputListBox example code from:

https://github.com/InventorCode/iLogicRules/blob/master/snippets/InputListBox-example.vb

Any ideas on how to prevent this?

Re: Unhandled Exception when using InputListBox

WCrihfield — Fri, 14 Aug 2026 11:29:39 GMT

Hi @steinarr34755. Have you read through the following Inventor Programming Forum discussion topic yet. It is primarily about the InputListBox, and relatively new problems mentioned by another user recently. If not, it may contain some useful information for your situation, because it has a lot of similarities. It also has multiple accepted solutions, some of which may work for you too.

https://forums.autodesk.com/t5/inventor-programming-forum/critical-inventor-2027-ilogic-regression-inputlistbox-no-longer/m-p/14074996

Re: Unhandled Exception when using InputListBox

josebaqueror — Sun, 16 Aug 2026 01:44:43 GMT

Since it reproduces with the canonical InputListBox example and your result still comes through correctly, this is an internal exception inside iLogic's dialog surfacing as a popup in 2026.2, not something in your rule. A Try/Catch around the InputListBox call usually won't suppress it, because it's thrown and handled inside the dialog, not on your side. Two practical routes: 1. For production rules, swap InputListBox for your own small dialog. A System.Windows.Forms form with a ListBox and ShowDialog (or a tiny WPF window) gives you the same selection with full control and no surprise popup. It's a few lines and stable across versions. 2. If you want to stay on InputListBox, report it to Autodesk with exactly what you posted (the sample code plus 2026.2). Reproducing on the documented sample is a strong bug report. Does it also happen on an older release, or only 2026.2? If it's only 2026.2 it's almost certainly a regression in that build.

Re: Unhandled Exception when using InputListBox

lauri_barnhart — Mon, 17 Aug 2026 15:36:21 GMT

Welcome to the community, @steinarr34755.

Checking in to see if the information provided by WCrihfield or josebaqueror clarified your question. If either post did, please consider clicking on the 'Accept Solution' button on the post(s) that provided the clarity. If you still need assistance, please update here.

Best,