Event subscriber arguments should use identifier syntax (LC0028)

Since Business Central 2023 wave 1 (BC22), event subscriber arguments support identifier syntax instead of string literals. Using identifiers unlocks powerful Visual Studio Code navigation features such as Go To Definition, Go To References, tooltips, and CodeLens reference counts.

This rule reports a diagnostic when event subscriber attribute parameters still use the old string literal syntax (single quotes) instead of the new identifier syntax.

Why this matters

When event subscriber arguments use string literals, the AL Language extension cannot resolve the reference. This means no navigability — you can’t jump to the event publisher, see who else subscribes, or get tooltips.

Switching to identifier syntax enables:

  • Go To Definition (F12) — Jump directly to the event publisher method.
  • Go To References (Shift+F12) — See all subscribers of a given event.
  • Tooltips — Hover over the event name to see its definition.
  • CodeLens — See how many references exist for each event publisher.

Go To Definition navigates directly to the event publisher.

Example

The following event subscriber uses the old string literal syntax with single quotes around the event publisher name and the event name:

codeunit 50100 MyCodeunit
{
    [EventSubscriber(ObjectType::Codeunit, Codeunit::"Sales-Post", 'OnAfterPostSalesDoc', '', false, false)]
    local procedure OnAfterPost(var SalesHeader: Record "Sales Header")
    begin
    end;
}

Old syntax: event name in single quotes — no navigability.

To fix this, replace the single-quoted string literals with identifiers. For simple names, remove the quotes entirely. For names containing spaces, use double quotes instead:

codeunit 50100 MyCodeunit
{
    [EventSubscriber(ObjectType::Codeunit, Codeunit::"Sales-Post", OnAfterPostSalesDoc, '', false, false)]
    local procedure OnAfterPost(var SalesHeader: Record "Sales Header")
    begin
    end;
}

New syntax: event name as identifier — full VS Code navigability.

Code action

A code action is available for this diagnostic. The AL Language extension provides a built-in code action to convert event subscriber parameters from string literal to identifier syntax. This can be applied to a single instance, the active file, the active project, or the entire workspace.

Use the AL code action to convert from string literals to identifiers.

See also