For循环不会将值添加到点集合

for循环不会为我的points集合添加任何值:

Esri.ArcGISRuntime.Geometry.PointCollection VMM40Points = new Esri.ArcGISRuntime.Geometry.PointCollection(Spatialreference);
            for (int i = 1; i == xyz.Count/3; i += 3)
            {
                VMM40Points.Add(xyz[i - 1], xyz[i], xyz[i + 1]);
            }

this is the debugger: https://i.stack.imgur.com/7ZXwA.png