Update:

I switched the reference to the Core.dll and that caused more issues and still did not work.

Does anyone have any good ideas on how I can proceed with the tutorial?

UPDATE: After more comparison between the Sample Code, my code and the tutorial it seems that the referenced dll is different. In the Redist folder is specifically marked as .NET Core 3.0. The tutorial says to make a reference to: C:\GdPicture.NET 14\Redist\DocuVieware (.NET Framework 4.6)\GdPictur...

Visual Studio 2019 Version 16.5.1 GDPicture.NET.14 version is 3.1.0.68 I am following the tutorial for Core .Net 2.2 here . But I am running into an issue with the controller for the API, specifically the LoadFromFileMultipart() method. The IDE gives me this compile time error: Argument 1: cannot co...