/// <summary>
/// Start method. Invoked by MvvmCross on main view model
/// </summary>
public override void Start()
{
Shapes = new ObservableCollection <IShape>(_ShapesRepo.GetShapes());
SelectedShape = Shapes.FirstOrDefault();
_ShapesRepo.ShapeAdded += OnShapeAdded;
}
/// <summary>
/// Computes total area of all shapes
/// </summary>
/// <returns></returns>
public double ComputeTotalArea()
{
var shapes = _ShapesRepo.GetShapes();
return(shapes.Sum(shape => shape.CalculateArea()));
}
