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。
        Dim model As IpfcModel
5 a9 T! Q( z0 h; J        model = session.CurrentModel
        Dim assembly As IpfcAssembly
        assembly = CType(model, IpfcAssembly)
0 j; T2 P) X! Q5 I( K& P
        MsgBox(CType(assembly, IpfcSolid).ListFeaturesByType(True, EpfcFeatureType.EpfcFEATTYPE_DATUM_AXIS).Count.ToString())
. H7 ]' c9 `, m- j5 N& z* B        'MsgBox(CType(assembly, IpfcModelItemOwner).ListItems(EpfcModelItemType.EpfcITEM_AXIS).Count.ToString())

: R; y* r& Z! k% q4 h- }        Dim models As IpfcModels
% n4 |! r( N1 I5 `# Y5 R* f$ t" y        models = session.ListModels()
        Dim asmmodelitemowner As IpfcModelItemOwner
        asmmodelitemowner = CType(models(1), IpfcModelItemOwner)//获取到原先已经添加进来的圆柱作为modelitemowner

  [5 D! S2 Z$ g/ D: H' P+ B        Dim compmodelitemowner As IpfcModelItemOwner
        compmodelitemowner = CType(componentModel, IpfcModelItemOwner)//后来添加的圆柱owner
        Dim asmitem As IpfcModelItem
; E+ M$ p3 S/ [' R; r2 B        Dim compitem As IpfcModelItem
        Try
* [8 h  {: Z' _6 J/ O            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。
+ w, T* F5 ]: E3 J5 l+ U1 V            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。
& x" |. s) W6 J2 X  [& b            Dim constrains As IpfcComponentConstraints
+ d% b- }8 h# N            Dim constrain As IpfcComponentConstraint
; V" ^, J# j0 ~, b' \$ ?/ K            constrains = New CpfcComponentConstraints
5 M' i4 m" e- L3 d8 W            Dim ids As Cintseq
            Dim path As IpfcComponentPath
3 e/ Q/ |' }' l4 A' T. H6 q! E2 w$ w            ids = New Cintseq
            path = (New CMpfcAssembly).CreateComponentPath(assembly, ids)//创建一个path
; N8 x/ U( H; ~# m% Q; D( ~            Dim asmSelection As IpfcSelection
            Dim compSelection As IpfcSelection
//通过modelitem创建selection对象，作为下面的reference
- Q8 r0 {* z8 l8 B            asmSelection = (New CMpfcSelect).CreateModelItemSelection(asmitem, Nothing)
: K7 w( n/ a4 L2 [* a            compSelection = (New CMpfcSelect).CreateModelItemSelection(compitem, Nothing)

            constrain = (New CCpfcComponentConstraint).Create(EpfcComponentConstraintType.EpfcASM_CONSTRAINT_ALIGN)
            constrain.ComponentReference = asmSelection
            constrain.ComponentReference = compSelection
" L' e4 \$ @) R            'constrain.Offset = 10.0
6 E, j& h5 r5 d- M3 Y, J: V/ s            constrains.Insert(constrains.Count, constrain)
7 p1 z2 |8 c2 q. |            assemblycompfeat.SetConstraints(constrains, path)//执行到这儿的时候发生异常
            assembly.Regenerate(Nothing)
* ?/ h, p' v/ T1 v请大侠过目指点

lzkeane

constrain.ComponentReference = asmSelection
4 b% F7 C  N$ v0 ]/ _2 |            constrain.ComponentReference = compSelection
1 k, q. ?, @" D) o& @1 y+ [% C* L. y这里错了