[求助]：选择首尾相连直线的问题

mountains3

本人写了一段选择首尾相连直线的程序，但运行时有时能全部选中，有时不能，跟开始选择哪条直线有关，程序的逻辑我实在找不出什么错误，还请高手调试指点
Sub selline3()
On Error Resume Next
Dim selects As AcadSelectionSet
Dim i As Integer
Dim j As Integer
Dim k As Long
Dim startpoint As Variant
Dim endpoint As Variant
Dim entline As AcadEntity
Dim tolerance As Double
Dim enttoadd(0) As AcadEntity
Dim templine As AcadLine
Dim dir1 As Variant
Dim dir2 As Variant
Dim gpCode(1) As Integer
Dim dataValue(1) As Variant
Dim isdup As Boolean
Dim joinedline() As myline
Dim toaddline As myline
Dim groupCode As Variant, dataCode As Variant
    gpCode(0) = 0
    dataValue(0) = "AcDbLine"
    groupCode = gpCode
    dataCode = dataValue
ThisDrawing.SelectionSets.Item("r").Delete
If Err Then
Err.Clear
Set selects = ThisDrawing.SelectionSets.Add("r")
End If
selects.SelectOnScreen
If selects.Count = 0 Then
selects.Delete
Exit Sub
End If
tolerance = 0.01
For j = 1 To 2
For k = 0 To ThisDrawing.ModelSpace.Count - 1
Set entline = ThisDrawing.ModelSpace(k)
    If (entline.ObjectName = "AcDbLine") Then
     startpoint = entline.startpoint
     endpoint = entline.endpoint
        For i = 0 To selects.Count - 1
            Set templine = selects(i)
                dir1 = templine.startpoint
                dir2 = templine.endpoint
                If (Abs(dir1(0) - startpoint(0)) <= tolerance And Abs(dir1(1) - startpoint(1)) <= tolerance _
                    And Abs(dir1(2) - startpoint(2)) <= tolerance) Or (Abs(dir1(0) - endpoint(0)) <= tolerance _
                    And Abs(dir1(1) - endpoint(1)) <= tolerance _
                    And Abs(dir1(2) - endpoint(2)) <= tolerance) Then
                    Set enttoadd(0) = entline
                    selects.AddItems enttoadd
                    entline.Highlight True
                End If
                If (Abs(dir2(0) - startpoint(0)) <= tolerance And Abs(dir2(1) - startpoint(1)) <= tolerance _
                    And Abs(dir2(2) - startpoint(2)) <= tolerance) Or (Abs(dir2(0) - endpoint(0)) <= tolerance _
                    And Abs(dir2(1) - endpoint(1)) <= tolerance _
                    And Abs(dir2(2) - endpoint(2)) <= tolerance) Then
                    Set enttoadd(0) = entline
                    selects.AddItems enttoadd
                    entline.Highlight True
                End If
        Next
    End If
Next k
Next j
MsgBox selects.Count
selects.Delete
End Sub
在这里先行致谢了！