What kind of project is this? Are you trying to build a docking window for PI ProcessBook?
That usually really helps if you can give us more details about what you are trying to achieve as we may be able to consider other options that sometimes are not seen at the first place.
But, to give a little start on this I think you may find some information in this post:
David Hollebeek gave a good advice in the post, telling that because COM is involved, you may have side effects with garbage collection, please see post for more detailed information.
Other that that, I could also see that you have created another question very similiar to this one here: C# axPbd Do not work!
Do you think we can delete one to keep only on discussion thread?
Thanks for coming on PI Square and I am looking forward to learn more about your project!