问了几次了，多段线的长度怎么获得

Sub Count_len()
    ' 创建新的选择集
    Dim sset As AcadSelectionSet
For i = 0 To ThisDrawing.SelectionSets.Count - 1
ThisDrawing.SelectionSets.Item(i).Clear
ThisDrawing.SelectionSets.Item(i).Delete
Next
On Error Resume Next
    Set sset = ThisDrawing.SelectionSets.Add("SS0")
   sset.SelectOnScreen
     Dim entry As AcadEntity
    Dim l_text As String
    Dim l_l As Double
    Dim Arc_count As Integer
    Dim Line_count As Integer
    For Each entry In sset
        '如果是多段线或曲线的长度，就不行了
        If entry.ObjectName = "AcDbArc" Then
        l_text = l_text & "+" & entry.ArcLength
        l_l = l_l + entry.ArcLength
        Arc_count = Arc_count + 1
        ElseIf entry.ObjectName = "AcDbLine" Then
        l_text = l_text & "+" & entry.Length
        l_l = l_l + entry.Length
        Line_count = Line_count + 1
        End If
    Next entry
ThisDrawing.Utility.Prompt vbCrLf & Arc_count & "个弧," & Line_count & "条直线. 共" & Arc_count + Line_count & "个对象." & vbCrLf & l_text & "=" & l_l & vbCrLf
End Sub

Sub GetLength()
    Dim obj As AcadEntity
    Dim pnt As Variant
    ThisDrawing.Utility.GetEntity obj, pnt, "选取曲线："
    Dim leng As Double
    leng = GetCurveLength(obj)
    MsgBox "所选曲线的长度为 " & leng, , "乐筑天下VBA示例"
End Sub
Public Function GetCurveLength(curve As AcadEntity) As Double
    Dim obj As VLAX, retVal
    
    Set obj = New VLAX
    obj.EvalLispExpression "(setq curve (handent " & Chr(34) & curve.Handle & Chr(34) & "))"
    obj.EvalLispExpression "(setq curvelength (vlax-curve-getDistAtParam curve " & _
                           "(vlax-curve-getEndParam curve)))"
    retVal = obj.GetLispSymbol("curvelength")
    obj.NullifySymbol "curve", "curvelength"
    Set obj = Nothing
    GetCurveLength = CDbl(retVal)
End Function