It is difficult to say what is going on, not being able to see the project or code, so let’s just start from the beginning. I will be using vs2019:
From the link in your first post, I installed the Rhino sdk tools, since I did not have these installed for my vs2019:
From the linked page I followed the link for installing the RhinoCommon templates:
That link led here, and I clicked the download button:
This downloaded a .vsix file, so I made sure vs2019 was not running, and double-clicked the .vsix file to install it:
The installer ran successfully, I started vs2019, and chose Create a new project:
I then browsed to the C# RhinoCommon plugin for Rhino 7 project type and clicked Next:
I set up the project as desired and clicked Create:
The extension then showed a dialog with some more options:
Looks ok, so clicked Finish, and I got my solution:
Clicking main menu > Build > Build Solution, the solution built fine:
By default the main plugin file looks like this:
Overriding the OnLoad method looks like this:
Inside of OnLoad, we can replace the code with that from Dale’s example:
We have some errors, which will be taken care of by two using
statements:
With those errors fixed, the solution once again builds successfully:
So, try following through these steps, and you can then move forward from there, once you have it working.