A simple point collection would not work on a 2d polyline, and since these are simple wrappers around ObjectARX classes, you are in the same boat.
Here is some code to get at pline2d and 3d, the 2d code generates an offset polyline and gets the data.
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Public Shared Sub TestPline()
Dim editor As Editor = Application.DocumentManager.MdiActiveDocument.Editor
Dim db As Database = Application.DocumentManager.MdiActiveDocument.Database
Dim trans As Transaction = db.TransactionManager.StartTransaction()
Try
Dim prEnt As New PromptEntityOptions("Select a polyline:")
Dim prEntRes As PromptEntityResult = editor.GetEntity(prEnt)
If prEntRes.Status PromptStatus.OK Then Return
Dim id As ObjectId = prEntRes.ObjectId
' get input polyline
Dim ent As Entity = DirectCast(trans.GetObject(id, OpenMode.ForRead), Entity)
Dim pl As Polyline = DirectCast(ent, Polyline)
Dim curves As DBObjectCollection = pl.GetOffsetCurves(2.0)
Dim i As Integer
Dim s As String
For i = 0 To curves.Count - 1
Dim newPl As Polyline = DirectCast(curves.Item(i), Polyline)
Dim isNew As Boolean = newPl.IsNewObject
Dim numSegs As Integer = newPl.NumberOfVertices
If newPl.Closed = False Then numSegs -= 1
Dim j As Integer
For j = 0 To numSegs - 1
Dim segType As SegmentType = newPl.GetSegmentType(j)
If segType = SegmentType.Line Then
Dim seg2 As LineSegment2d
Dim seg3 As LineSegment3d
seg2 = newPl.GetLineSegment2dAt(j)
seg3 = newPl.GetLineSegmentAt(j)
ElseIf segType = SegmentType.Arc Then
Dim a2 As CircularArc2d = newPl.GetArcSegment2dAt(j)
Dim a3 As CircularArc3d = newPl.GetArcSegmentAt(j)
End If
Next
Next
curves.Dispose()
'MsgBox(s)
trans.Commit()
Catch ex As Exception
trans.Abort()
MsgBox(ex.Message)
Finally
trans.Dispose()
End Try
End Sub
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Public Shared Sub TestPline3d()
Dim editor As Editor = Application.DocumentManager.MdiActiveDocument.Editor
Dim db As Database = Application.DocumentManager.MdiActiveDocument.Database
Dim trans As Transaction = db.TransactionManager.StartTransaction()
Try
Dim prEnt As New PromptEntityOptions("Select a 3d polyline:")
Dim prEntRes As PromptEntityResult = editor.GetEntity(prEnt)
If prEntRes.Status PromptStatus.OK Then Return
Dim id As ObjectId = prEntRes.ObjectId
' get input polyline
Dim ent As Entity = DirectCast(trans.GetObject(id, OpenMode.ForRead), Entity)
Dim pl As Polyline3d = DirectCast(ent, Polyline3d)
Dim c As Curve = DirectCast(pl, Curve)
' the magic trick is first line segment on 3dpoly is 0.0 to 1.0,
' 2nd line seg is 1.0 to 2.0, rinse and repeat
Dim sp As Double = c.StartParam
Dim ep As Double = c.EndParam
Dim outPts As String
Dim p As Double
For p = sp To ep Step 1.0
Dim pt As Point3d = c.GetPointAtParameter(p)
outPts &= String.Format(" {0},{1},{2} ", pt.X, pt.Y, pt.Z) & vbCrLf
Next
MsgBox(outPts)
trans.Commit()
Catch ex As Exception
trans.Abort()
MsgBox(ex.Message)
Finally
trans.Dispose()
End Try
End Sub
