Support Article
Cannot pass parameters to When rule
SA-25008
Summary
The visible When condition using a parameterized When rule does not show the parameters in the dialog.
Error Messages
Not Applicable.
Steps to Reproduce
- Make a When rule that use parameters.
- Add parameters in the parameters page of the When rule and Save.
- Try to use the When rule on a visibility of a UI. No parameter fields will appear to fill them.
Root Cause
When rules do not have context sensitive parameter configuration (when the parameters appear automatically when it is configured in the UI). Instead you need to set the parameter values in advance through a data transform.
This is mentioned in the following help topic:
https://pdn.pega.com/sites/pdn.pega.com/files/help_v72/procomhelpmain.htm#rule-/rule-obj-/rule-obj-when/parameters.htm
Complete this optional tab to refer to parameters (using the syntax param.name) as inputs on the Advanced tab.
If used as a source of values, the parameter values must be set (for example, using a data transform) before the when condition runs.
Resolution
Use a "Before this action" Data Transform or Activity on the flow action to set parameter values using the param.paramname syntax.
Published July 4, 2016 - Updated October 8, 2020
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