form-pattern-scaffolding

name: form-pattern-scaffolding description: Scaffold an AxForm in D365 Finance & Operations using one of the nine canonical patterns (SimpleList, SimpleListDetails, DetailsMaster, DetailsTransaction, Dialog, TableOfContents, Lookup, ListPage, Workspace), or create a Display / Action / Output menu item. Invoke whenever the user asks to "create a form", "scaffold a list page", "make a dialog", "build a workspace", "create a menu item", "add a Display menu item", or "add an Action menu item". applies_when: User intent mentions creating an AxForm, choosing a form pattern, list pages, master records, dialogs, lookups, workspaces, details/transaction (header+lines) forms, or creating a Display / Action / Output menu item.

⛔ NEVER write X++ AOT XML files directly via PowerShell, terminal file commands (Set-Content, Out-File, New-Item), editor write tools, or any raw text approach. The XML schema (<AxClass>, <AxTable>, <AxForm>, <Methods>, <SourceCode>) is proprietary — LLMs have not been trained on it reliably. ALWAYS use d365fo generate … commands to produce correct AOT XML. If d365fo is unavailable in PATH, stop and ask the user to install it.

Authoring AxForm XML — pattern-correct

The CLI's d365fo generate form mirrors d365fo-mcp-server's generate_object (objectType=form). The nine D365FO patterns are validated against real AOT forms (CustGroup, PaymTerm, CustTable, SalesTable, …). Hand-rolled XML loses ActionPane, QuickFilter, FastTabs, the right PatternVersion, and the design-time hooks Visual Studio expects — never hand-roll.

⛔ Anti-pattern: escalating workarounds

WRONG SPIRAL (each step is more wrong):
 1. "I'll write the AxForm XML by hand"
 2. "It's only 3 elements, I'll skip ActionPane / QuickFilter"
 3. "PatternVersion 1.0 is fine instead of 1.1"
 4. "I'll add SimpleList without grid columns"

CORRECT — always:
 d365fo generate form <Name> --pattern <P> --table <T> --field <F1> --field <F2> --install-to <Model>

Pre-flight

d365fo search form <Name> --output json          # collision check
d365fo get table <PrimaryTable> --output json    # field list for the grid

# Pattern spec — required structure, versions, when-to-use, reference forms
d365fo form-pattern spec --output json                  # list all known patterns + sub-patterns
d365fo form-pattern spec DetailsMaster --output json    # full structural spec for one pattern

# Pattern reconnaissance — what do peers use for THIS table / similar entities?
d365fo find form-patterns --table <PrimaryTable> --output json
d365fo find form-patterns --similar-to <ReferenceForm> --output json
d365fo find form-patterns --pattern SimpleList --output json   # pattern catalogue

The analyzer (d365fo find form-patterns) reads <Design><Pattern> from every indexed AxForm. Use it instead of guessing — pass the most-common peer pattern straight into --pattern on the next step. With no flags it returns a histogram so you can see what shapes exist before drilling in.

When the user provides an existing form as an example, treat it as a pattern contract, not as optional inspiration:

d365fo get form <ExampleForm> --output json
d365fo find form-patterns --similar-to <ExampleForm> --output json

Use the same pattern family unless the user explicitly requests a different one. After generation, verify that the new form still contains the pattern's required scaffolding: datasource(s), design pattern/version metadata, required ActionPane/Body/Tab/FastTab/grid/QuickFilter controls, and required line/header datasources for transaction forms. Missing pattern elements are a failed generation even if the XML is well-formed.

Pattern catalog

Aliases recognised: master, transaction, toc, panorama, drop-dialog, dropdialog, simplelist-details, etc.

Scaffolding examples

# Master form for a vehicle table
d365fo generate form FmVehicle \
    --pattern master \
    --table FmVehicle \
    --field VIN --field Make --field Year \
    --section General:"@SYS:General" \
    --section Notes:"@SYS:Notes" \
    --install-to FleetManagement

# Order header + lines (DetailsTransaction)
d365fo generate form FmOrder \
    --pattern transaction \
    --table FmOrderHeader \
    --lines-table FmOrderLine \
    --field OrderId --field CustAccount --field DeliveryDate \
    --install-to FleetManagement

# Dialog (no primary datasource needed)
d365fo generate form FmRunImport --pattern dialog --install-to FleetManagement

# Workspace with two panorama sections
d365fo generate form FmFleetWorkspace \
    --pattern workspace \
    --section Recent:"@Fleet:Recent" \
    --section Pending:"@Fleet:Pending" \
    --install-to FleetManagement

--field <F> is repeatable — these become grid / detail columns. The section template is --section Name:Caption (split on the first :).

Hard rules

• Never hand-roll AxForm XML — always use --pattern.
• generate form runs a structural pattern self-test (FP001–FP010) before writing; structural violations (unknown pattern, missing required controls, wrong order, disallowed children, misapplied sub-patterns) block the write while D365FO_FORM_PATTERN_ENFORCE=true (the default). Don't bypass the gate — fix the structure (d365fo form-pattern spec <P> shows the required tree).
• After editing form XML by hand or via an example, validate it: d365fo form-pattern validate <file> --output json (exit 2 = structural errors).
• Never skip the primary datasource for SimpleList / Lookup / ListPage / Master / Transaction patterns.
• Never drop required pattern controls or metadata from a generated form copied from an example. Validate against the example's pattern before finishing.
• Never rewrite an existing AxForm or AxFormExtension XML file wholesale. Preserve unrelated <Controls>, <DataSourceModifications>, <DataSourceReferences>, <DataSources>, methods, extension properties, and pattern metadata exactly.
• After changing form XML, validate XML well-formedness, run d365fo validate xpp --file <file> --code-type xml-any --output json, run d365fo index refresh --model <Model>, and re-read with d365fo get form <Form> --output json.
• Never use Dialog or TableOfContents patterns for transactional grids.
• Pre-flight search form <Name> before scaffolding to avoid collisions.
• Caption strings must be labels (BP BPErrorLabelIsText) — never raw text.
• After scaffolding, run d365fo build only on user request.

FormRun lifecycle & extension points

Forms follow a strict initialization order. Extension code must respect it.

Initialization sequence:

1. form.init() — form structure loaded; data sources NOT yet active.
2. FormDataSource.init() — each data source initializes (link types resolved).
3. form.run() — form becomes visible.
4. FormDataSource.executeQuery() — initial data load.

Common extension points (via CoC or event handlers):

Key form interaction APIs:

• FormDataSource.research(retainPosition: true) — refresh grid, keep cursor position.
• element.args() — access caller context (menu item, record, enum parameter).
• FormDataSource.queryBuildDataSource() — underlying QueryBuildDataSource for runtime range manipulation.
• FormDataSource.filter(fieldNum, value) / removeFilter(fieldNum) — programmatic quick-filter.
• element.design().controlName(formControlStr(MyForm, MyControl)) — access control by name at runtime.

Rules:

• Use d365fo get form <Name> --output json to find exact control names before wrapping.
• NEVER guess control names — they differ from field names and are often prefixed.
• Cannot add new methods via CoC on formdatasourcestr/formdatafieldstr/formControlStr — only wrap methods that already exist.

Menu items

Menu items are the AOT entry points that open a form, call a class action, or trigger a report. Always scaffold the menu item alongside or after the target form.

# Display menu item — opens a form (most common)
d365fo generate menu-item FmCustomersMenuItem \
  --kind Display --object FmCustomers --object-type Form \
  --label "@Fleet:Customers" \
  --install-to FleetManagement

# Action menu item — calls a class runnable (batch/service)
d365fo generate menu-item FmPostOrdersAction \
  --kind Action --object FmPostOrdersService --object-type Class \
  --label "@Fleet:PostOrders" \
  --install-to FleetManagement

# Output menu item — triggers a report
d365fo generate menu-item FmOrdersReportMenuItem \
  --kind Output --object FmOrdersReport --object-type Report \
  --label "@Fleet:OrdersReport" \
  --install-to FleetManagement

Hard rules:

• One menu item per AOT type (AxMenuItemDisplay, AxMenuItemAction, AxMenuItemOutput) — naming convention <ObjectName>MenuItem or <ObjectName>Action.
• Do not create an Action menu item pointing to a form — use Display.
• After creating a menu item, it must be added to a menu or a security privilege to be reachable.