Since the last update from SW19 to SW20, I've suffered some problems to launch my old APIs in the new version. In fact, I'm in the first step (opening an exiting part) and I'm not able to get it. For that reason, I've begun with the example 2020 SOLIDWORKS API Help - Open Document Example (VB.NET) but, for some reason, the SW window starts but the part is not charged... so, when I refer to "doc" in the last line, it launches to me the error "Null Reference". Logically, I've checked that this part can be opened with a double-click
I've tried everything that I can think of, so I would appreciate any help.
Thank you in advance.