Cant not use Polyline.Item in c#

[pythonuser]

hi:
in the sdk online off c# I cant found the property Item off polyline, but in vs, I cant not use it, it is have change in the new sdk ? if not, how cant I use it?

[DavidRutten]

mesh.Vertices.Add(p1[i]);

[pythonuser]

think you @DavidRutten