Error in Creating the Custom workflow analyzer methods

I was following the instructions to create a custom workflow analyzer using the examples provided in link : Building Custom Rules
implemented only the Variable naming portion. getting the attached screenshot.

.NET Framework 4.6.1 DLL is placed
UiPath : 2021.10.4

@ppr any thoughts as you were helpful earlier.

Placed the new dll in Rules folder in program files it detected the new rule but when i clicked the analyzed project getting this error any suggestions.


This is a generic exception that occurs when you incorrectly create a variable as argument with out or In/Out property and do not pass any value into or out.
*Try choosing the correct property for an argument (In/Out).
*If argument not required then use a variable.

Try troubleshooting from this perspective. You could find the issue.

Sruthi YNM

1 Like


Looking at the RuleID we would assume that the error comes from your custom rule

@StefanSchnell has started a discussion on rule naming conventions

we would suggest to follow as close as possible the conventions (makes also easier to identify/group the rues). In my case we handled this as we used the Company Token within the RuleID on the last part:

The error looks that somewhere a Regex pattern? is null. Maybe remote debugging of the rule will help you to sort it out:

  • attach to remote process - UiPath.Studio.Analyzer
  • set a breakpoint somewhere you would assume the issue
  • start debugging
  • analyze it within the different inspection panels

Thanks for helping as always.

  1. Where we can find an example of
    IProjectModel, IActivityModel
    for adding the custom workflow analyzer rules.

  2. Is there any detailed course which we can learn on the Class layout and implementation to effectively work on the Custom workflow analyzer please let me know.

All the examples talk about the same one workflowmodel and not the other two.

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