If you have an actual Polyline (i.e. not a PolylineCurve or PolyCurve) you can/should call GetSegments on it. You can cast by setting the input typehint (this is Python, but it’s the same in C#):
Or in the code itself:
Example_PolylineGetSegments.gh (16.8 KB)
PS. you can syntax lightlight your code here on Discourse using markdown.