public void UpdateRing()
{
if (!double.IsNaN(Radius) && Radius > 0 && Center != null && PointCount > 2)
{
PointCollection pnts = new PointCollection();
for (int i = PointCount; i >= 0; i--)
{
double rad = 2 * Math.PI / PointCount * i;
double x = Math.Cos(rad) * Radius + Center.X;
double y = Math.Sin(rad) * Radius + Center.Y;
pnts.Add(new MapPoint(x, y));
}
if (Rings.Count == 0)
{
Rings.Add(pnts);
}
else
{
Rings[0] = pnts;
}
}
else
{
Rings.Clear();
}
}