TGIS_LayerVectorEnumerator class

DK11 for Delphi | GisLayerVector.TGIS_LayerVectorEnumerator | Classes | Constructors | Methods | Properties

Vector layer enumerator.

Available also on: .NET | Java | ActiveX | Python.

// Delphi
type
  TGIS_LayerVectorEnumerator = class( TObject )
  end;

// C++ Builder
class PASCALIMPLEMENTATION TGIS_LayerVectorEnumerator : public TObject
{
};

→ TObject

There is no garbage collector for TGIS_LayerVectorEnumerator instances. Because of this, the layer enumerator must be destroyed, by calling TGIS_LayerVectorEnumerator.Free, after it has been used. Check examples below.

// Indirect use
var
  shp : TGIS_Shape ;
begin
  // automated enumerators
  for shp in layer.Loop( some_extent ) do begin
    dosomething();
  end ;
end ;
 
// Direct use by using layer's Enumerator Factory
var
  shp : TGIS_Shape ;
  en  : TGIS_LayerVectorEnumerator ;
begin
  en := layer.Loop( some_extent ).GetEnumerator ;
  while en.MoveNext do begin
    shp := en.GetCurrent ;
    dosomething();
  end ;
  en.Free ;
end ;
 
// Direct use by using enumerator constructor
var
  shp : TGIS_Shape ;
  en  : TGIS_LayerVectorEnumerator ;
begin
  en := TGIS_LayerVectorEnumerator.Create(
          layer, some_extent, '', nil, '', True
        ) ;
  while en.MoveNext do begin
    shp := en.Current ;
    dosomething();
  end ;
  en.Free ;
end ;