Hi,
The Entity type have a LineWeight property which is a LineWeight enum type.
From the docs:
public enum LineWeight {
ByBlock = -2,
ByLayer = -1,
ByLineWeightDefault = -3,
LineWeight000 = 0,
LineWeight005 = 5,
LineWeight009 = 9,
LineWeight013 = 13,
LineWeight015 = 15,
LineWeight018 = 0x12,
LineWeight020 = 20,
LineWeight025 = 0x19,
LineWeight030 = 30,
LineWeight035 = 0x23,
LineWeight040 = 40,
LineWeight050 = 50,
LineWeight053 = 0x35,
LineWeight060 = 60,
LineWeight070 = 70,
LineWeight080 = 80,
LineWeight090 = 90,
LineWeight100 = 100,
LineWeight106 = 0x6a,
LineWeight120 = 120,
LineWeight140 = 140,
LineWeight158 = 0x9e,
LineWeight200 = 200,
LineWeight211 = 0xd3
}
Using example:
Line line = new Line(new Point3d(0,0,0),new Point3d(0,10,0));
line.LineWeight = LineWeight.LineWeight035;