Gettig错误：类型为...的对象没有len（）

Question

我试图从在NX软件中以Python打开的工作零件文件中获取PMI计数，但出现错误：

TypeError: object of type 'NXOpen.Annotations.PmiCollection' has no len()

代码：

lw = theSession.ListingWindow
lw.Open()
theSession  = NXOpen.Session.GetSession()
theParts = theSession.Parts
theWorkPart = theParts.Work
allPMIObjects = theWorkPart.PmiManager.Pmis
count1 = len(allPMIObjects)
lw.WriteLine(count1)
lw.Close()

文档链接：https://docs.plm.automation.siemens.com/data_services/resources/nx/11/nx_api/custom/en_US/nxopen_python_ref/NXOpen.Annotations.PmiCollection.html

等效的vb代码：http://nxjournaling.com/content/find-out-if-part-has-any-pmi

Answer 1

以下是提供活动部件中PMI计数并断言计数是否更改的代码（此处为3）：

lw = theSession.ListingWindow
lw.Open()
# Custom code starts to get PMI count in part and check
theSession  = NXOpen.Session.GetSession()
theParts = theSession.Parts
theWorkPart = theParts.Work
allPMIObjects = theWorkPart.PmiManager.Pmis
i = 0
for p in allPMIObjects:
    i = i + 1
lw.WriteLine(str(i))
lw.Close()

#if PMI count is changed from 3, raise AssertionError:
assert i == 3