a4d85c3e9e
Second contribution from CURABIS ApS, generalized from patterns observed across real AppSource/PTE development. Cross-checked against the current microsoft/knowledge corpus before opening; several originally-drafted candidates were dropped as duplicates of existing files.
2 KiB
| bc-version | domain | keywords | technologies | countries | application-area | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
style |
|
|
|
|
Keep business logic out of page objects
Description
A page procedure that calculates a value and assigns it to a field, calls Rec.Modify() directly, or implements a business rule is an architecture violation even when it compiles. Pages are a presentation layer: they bind data to the UI and invoke actions. Calculations, validations, and record mutations belong in codeunits, where they can be tested, reused, and called consistently regardless of which page (or API, or batch job) triggers them. When logic lives on a page, it only applies when a user opens that specific page — the same business rule silently doesn't run through any other entry point.
A narrow set of patterns are conventional rather than violations:
- A setup page reading and writing its own singleton setup record.
- A dedicated "Run Conversion" page invoking a conversion codeunit directly.
- The standard singleton-initialization idiom on
OnOpenPage(if not Rec.Get() then begin Rec.Init(); Rec.Insert(); end) used by cue/activities pages to bootstrap their own presentation-state record — this is not business logic, it is the same pattern used throughout base-app cue pages.
Best Practice
Delegate all business operations to a codeunit: the page owns presentation, the codeunit owns logic. A calculation or validation triggered from a page action should call a codeunit procedure rather than compute the result inline.
See sample: pages-must-not-contain-business-logic.good.al.
Anti Pattern
Direct calculations in a page trigger (e.g. Rec."Total Amount" := Rec.Quantity * Rec."Unit Price"), calls to Rec.Modify() from a page trigger, or business-rule validation embedded in OnValidate/OnAction instead of routed through a codeunit.
See sample: pages-must-not-contain-business-logic.bad.al.