'宣言 Protected Overridable Function GetBuckets( _ ByVal viewportRect As Rect, _ ByVal visibleItems As List(Of Integer), _ ByVal resolution As Double, _ ByVal itemLocations As IList(Of Point) _ ) As Dictionary(Of Integer,MarkerManagerBucket)
protected virtual Dictionary<int,MarkerManagerBucket> GetBuckets( Rect viewportRect, List<int> visibleItems, double resolution, IList<Point> itemLocations )