不确定顶点数目的情况下怎么绘制多段线？

  Dim index As Integer   
    index = 2
    
    Dim pt1 As Variant
    pt1 = ThisDrawing.Utility.GetPoint(, "输入第一点:")
    If Err Then                     
        Err.Clear
        Exit Sub
    End If
    Dim ptPrevious As Variant, ptCurrent As Variant       
    ptPrevious = pt1
    
nextpt:
    ptCurrent = ThisDrawing.Utility.GetPoint(ptPrevious, "输入下一点:")
    If Err Then                    
        Err.Clear
        Exit Sub
    End If
    
    Dim objPline As AcadLWPolyline
    If index = 2 Then
        Dim points(0 To 3) As Double
        points(0) = ptPrevious(0)
        points(1) = ptPrevious(1)
        points(2) = ptCurrent(0)
        points(3) = ptCurrent(1)
        Set objPline = ThisDrawing.ModelSpace.AddLightWeightPolyline(points)
    ElseIf index > 2 Then
        Dim ptVert(0 To 1) As Double
        ptVert(0) = ptCurrent(0)
        ptVert(1) = ptCurrent(1)
        objPline.AddVertex index - 1, ptVert
    End If
    index = index + 1
    ptPrevious = ptCurrent
    GoTo nextpt