DK11 for .NET | TatukGIS.NDK.TGIS_LayerVector.FindFirst | Overloads | Constructors | Fields | Methods | Properties | Events
Finds the first occurrence of an item which meets an extent. Will use RTree if available.
// C# public virtual TGIS_Shape FindFirst( TGIS_Extent _extent );
' VisualBasic Public Overridable Function FindFirst( ByVal _extent As TGIS_Extent ) As TGIS_Shape
// Oxygene public function FindFirst( _extent : TGIS_Extent ) : TGIS_Shape; virtual;
Name | Type | Description |
---|---|---|
_extent | TGIS_Extent | extent of items to be found; the layer has been attached to the Viewer then expected _extent units are in a Viewer coordinate space; otherwise expected _extent units are in a Layer coordinate space |
Type | Description |
---|---|
TGIS_Shape | Shape itself or nil. |
See: FindNext
Use this method to find to the first shape in the layer matching given criteria. Using _query param we can narrow the result of the shape searching down to the minimum. This should speed up our process of locating a desired shape.
To locate a shape, simply choose an existing layer and use FindFirst method of with a proper extent and a SQL query as a WHERE clause.