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
, J, ^: Z, f7 X$ \        model = session.CurrentModel
4 M+ O1 x. f, n0 p        Dim assembly As IpfcAssembly
  r* n2 t1 A" t+ z* f  c/ ~: D        assembly = CType(model, IpfcAssembly)

        MsgBox(CType(assembly, IpfcSolid).ListFeaturesByType(True, EpfcFeatureType.EpfcFEATTYPE_DATUM_AXIS).Count.ToString())
% D( f; K9 S" O$ G        'MsgBox(CType(assembly, IpfcModelItemOwner).ListItems(EpfcModelItemType.EpfcITEM_AXIS).Count.ToString())

        Dim models As IpfcModels
        models = session.ListModels()
3 w. ]+ _( ?0 }$ y& K0 C7 Y        Dim asmmodelitemowner As IpfcModelItemOwner
7 j; w3 G0 f& Z$ q; |$ x        asmmodelitemowner = CType(models(1), IpfcModelItemOwner)//获取到原先已经添加进来的圆柱作为modelitemowner

7 j1 @: r# Y/ T1 ~! [        Dim compmodelitemowner As IpfcModelItemOwner
8 W# a" k: `. H6 o4 [9 `+ q3 w        compmodelitemowner = CType(componentModel, IpfcModelItemOwner)//后来添加的圆柱owner
        Dim asmitem As IpfcModelItem
        Dim compitem As IpfcModelItem
        Try
! _) [% h2 m% V! V, N8 u# N            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。
, n  S6 o+ T: E* t/ @. L! `2 P            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。
- ?/ Y/ Z" R7 L8 X+ n) E            Dim constrains As IpfcComponentConstraints
4 }! D, }: X9 y3 P  W7 H! H6 E            Dim constrain As IpfcComponentConstraint
3 L/ R% @- d# A: ?            constrains = New CpfcComponentConstraints
4 b# Y2 @, B; [0 l/ _            Dim ids As Cintseq
) `9 ?: p5 j0 e7 q# J  s: Y+ g/ P( x$ @            Dim path As IpfcComponentPath
8 z+ ]( G( [' D+ d            ids = New Cintseq
            path = (New CMpfcAssembly).CreateComponentPath(assembly, ids)//创建一个path
- i8 l. [$ B6 |& {            Dim asmSelection As IpfcSelection
            Dim compSelection As IpfcSelection
//通过modelitem创建selection对象，作为下面的reference
+ u( {; F% r$ \3 t. C! o            asmSelection = (New CMpfcSelect).CreateModelItemSelection(asmitem, Nothing)
            compSelection = (New CMpfcSelect).CreateModelItemSelection(compitem, Nothing)
" h( R8 h$ g1 z( e0 S
4 V5 N0 o, c5 H. ~7 C            constrain = (New CCpfcComponentConstraint).Create(EpfcComponentConstraintType.EpfcASM_CONSTRAINT_ALIGN)
            constrain.ComponentReference = asmSelection
' a: A' b: M0 n( }            constrain.ComponentReference = compSelection
            'constrain.Offset = 10.0
9 ^. r6 W5 M( \. }( O  O1 X, J            constrains.Insert(constrains.Count, constrain)
            assemblycompfeat.SetConstraints(constrains, path)//执行到这儿的时候发生异常
            assembly.Regenerate(Nothing)
7 k0 T. E# T% @7 `5 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