proe二次开发：装配添加约束求救

mydear

现在我在装配体里面有一个圆柱体，我现在通过程序将另外一个圆柱体添加进来并进行约束添加，添加进来了，但是我在添加约束的时候老是发生异常，我把代码贴出来大家看看帮帮忙吧。
% T! q' T4 y  V  H        Dim model As IpfcModel
$ X: V+ U! I  l: W: q        model = session.CurrentModel
        Dim assembly As IpfcAssembly
  Z; Q& g( W! o/ K* X        assembly = CType(model, IpfcAssembly)
. h. z! H1 i# B  P
: {4 u  v: T9 p) O& p2 Q        MsgBox(CType(assembly, IpfcSolid).ListFeaturesByType(True, EpfcFeatureType.EpfcFEATTYPE_DATUM_AXIS).Count.ToString())
) M8 S. t3 d& }7 p) i+ X+ j, i        'MsgBox(CType(assembly, IpfcModelItemOwner).ListItems(EpfcModelItemType.EpfcITEM_AXIS).Count.ToString())
* y: N# d5 G0 Q+ p2 N! x7 E% q
        Dim models As IpfcModels
        models = session.ListModels()
0 y# D: S- j  f# T        Dim asmmodelitemowner As IpfcModelItemOwner
. \) D1 Z1 n2 s2 ?        asmmodelitemowner = CType(models(1), IpfcModelItemOwner)//获取到原先已经添加进来的圆柱作为modelitemowner
( Q' p7 m  F3 p' b
        Dim compmodelitemowner As IpfcModelItemOwner
3 y" x; K/ d4 b* g" E2 d# i+ ~) {        compmodelitemowner = CType(componentModel, IpfcModelItemOwner)//后来添加的圆柱owner
) N( X( ^' G* I/ M2 ]& y. M        Dim asmitem As IpfcModelItem
. ^$ q8 l1 F1 s        Dim compitem As IpfcModelItem
        Try
            asmitem = asmmodelitemowner.GetItemById(EpfcModelItemType.EpfcITEM_AXIS, Convert.ToInt32(assemblyitemID))//通过id获取我所选择的圆柱的中心轴。
6 }2 y) j" {4 @            compitem = compmodelitemowner.GetItemById(EpfcModelItemType.EpfcITEM_AXIS, Convert.ToInt32(componentitemID))//通过id获取我所选择的圆柱的中心轴。
            Dim constrains As IpfcComponentConstraints
            Dim constrain As IpfcComponentConstraint
            constrains = New CpfcComponentConstraints
/ {* z; Y; e0 f% @" j2 R            Dim ids As Cintseq
: s% j0 r9 W) i+ T2 R) d! W( o            Dim path As IpfcComponentPath
            ids = New Cintseq
            path = (New CMpfcAssembly).CreateComponentPath(assembly, ids)//创建一个path
            Dim asmSelection As IpfcSelection
  a  k4 w& X0 k$ o            Dim compSelection As IpfcSelection
//通过modelitem创建selection对象，作为下面的reference
            asmSelection = (New CMpfcSelect).CreateModelItemSelection(asmitem, Nothing)
            compSelection = (New CMpfcSelect).CreateModelItemSelection(compitem, Nothing)

9 B4 ?$ ^5 ~) z" [0 l* T2 ~            constrain = (New CCpfcComponentConstraint).Create(EpfcComponentConstraintType.EpfcASM_CONSTRAINT_ALIGN)
/ i% a; Z' O2 A* B- K            constrain.ComponentReference = asmSelection
  l" ?( f  x2 O" J) B/ b            constrain.ComponentReference = compSelection
# ]2 ~) t8 j  _( d            'constrain.Offset = 10.0
) d) l, ^6 D2 ?- y+ S; d            constrains.Insert(constrains.Count, constrain)
            assemblycompfeat.SetConstraints(constrains, path)//执行到这儿的时候发生异常
            assembly.Regenerate(Nothing)
5 y( j3 o+ R9 k! u请大侠过目指点

lzkeane

constrain.ComponentReference = asmSelection
4 b% F7 C  N$ v0 ]/ _2 |            constrain.ComponentReference = compSelection
这里错了