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Map

Map: TvxMap

Example​

procedure ScriptEvent(var Value: variant);
begin
  if Map <> nil then
    Value := Map.ModuleName
  else
    Value := Null;
end;

Usage​

Provides the active TvxMap when the script is executing for a custom map item.

Ownership, errors and performance

Velox owns the map. Never free it or retain it outside the current execution. Reading the bound reference is constant-time. Nil dereference and errors from called map members propagate; the variable itself performs no I/O.

Additional Technical Info​

Map exposes the live TvxMap associated with the current TvxCustomMapItem. Velox declares the name in every scripter so reusable script source can compile, but binds an instance only in a custom-map context.

The variable is a host-owned object reference and can be nil/unbound outside map execution.

Implementation

RegisterVariables always registers Map as TvxMap; the source comment explicitly says this allows other scripts such as Velox scriptlets to compile even though they cannot always reference a current custom map. During instance binding, Velox calls SetVarToInstance('Map', TvxCustomMapItem(MapItem).Map) only when MapItem is TvxCustomMapItem.

Behaviour and edge cases

  • Check for nil before dereferencing in reusable code or scriptlets.
  • A declared Map name does not prove that the current execution is a map event.
  • When assigned, it is the underlying map shared by the current map item, not a copy of configuration.
  • Different field/view map items can expose the same parent map. Do not use object identity to infer the current field/view; use the specific event context variables for that purpose.
  • A non-nil map does not prove that all views, fields, connections or modules are valid/enabled.
  • Treat the public reference as read-only context. Member calls can mutate map/execution state and should follow their documented contracts.

Related entries

  • Action and Flow expose the action that owns the current execution.
  • Source and Dest expose the surrounding data definitions.
Created 2026-07-15