TGIS_ShapeFieldChangeEvent prototype

DK for Delphi | GisLayerVector.TGIS_ShapeFieldChangeEvent | Methods | Classes | Prototypes

Callback type for shape attribute change events on Delphi platforms.

Available also on: Python.

// Delphi
type
  TGIS_ShapeFieldChangeEvent = procedure (
    _sender : TObject;
    _shp : TGIS_Shape;
    _id : Integer
  ) of object;

// C++ Builder
typedef void (_closure *TGIS_ShapeFieldChangeEvent)(
  TObject* _sender,
  TGIS_Shape* _shp,
  int _id
);

PURPOSE: Defines the callback signature used to notify listeners when a shape attribute value changes in a vector layer.

BEHAVIOR: The layer invokes this procedure after an attribute change and passes the sender, the affected TGIS_Shape instance, and the numeric field index from the layer schema.

CONSTRAINTS: The callback executes synchronously in the update context. The shape reference is valid only during the callback, and the field identifier is meaningful only for the owning layer schema.