Add Class Library reference to ASP.NET Core project - vb.net

Question

I am using VS Pro Update 3
I have been following the guide here: https://www.hanselman.com/blog/HowToReferenceAnExistingNETFrameworkProjectInAnASPNETCore10WebApp.aspx
I have 3 existing .NET 4.5.1 Class Libraries, written in VB.NET but I don't think that should matter as it's all on CLR.
My ASP.NET Core project is C#, targeting .NET 4.5.1.
Here is the Framework section of my project.json:
"frameworks": {
"net451": {
"dependencies": {
"WebApp.Api.Services": {
"target": "project"
}
}
}
},
If I add all my VB.NET class libraries using Add Existing Project to my solution and try to add them as project reference, I get the following error:
Project XXX type is unsupported by current project and cannot be added
as a reference
I also tried adding a C# class Library (WebApp.Api.Services), add VB.NET references to that, then add the C# Class Library as a reference to the ASP Core project
Doing this shows the references in Solution Explorer okay, it seems as though I can use types from the C# Class library but I can't use the VB.NET library's types in my code.
I also created a NuGet package, but no luck
I have read that you can create a 'wrapper' project somehow, or Visual Studio can do this automatically.
Has anyone ever tried adding VB.Net projects to ASP Core solution?

Answer 1

A project built for .NET Core cannot use class libraries built for .NET Framework. They are not directly compatible with each other. In fact I'm confused when you say:
My ASP.NET Core project is C#, targeting .NET 4.5.1.
If it's targeting .NET 4.5.1, then it's not actually a .NET Core project.
You should port your class libraries to .NET Standard; that way they can be used by a wide range of compatible frameworks. It is also possible to have a class library target multiple frameworks.

Answer 2

I managed to solve my issue.
The guide here is correct, I had another different issue that I didn't realize.
I found a System.BadImageFormatException error which lead me to the following question Start an asp.net core project as x86 under visual studio 2015
I uninstalled the x94 version of .NET Core and installed the x86 one.
I still could not add references to the VB.NET libraries to the ASP Core project, so my C# services 'Bridge' library was vital.
In my 'Bridge' library I have Models that I can return from my ASP Controllers:
Public BridgeModelA : VB.NETLibrary.ActualModelA
{
…
}
Then extensions
Public static VB.NETLibrary.ActualModelA ToModel(this BridgeModelA)
{
…
}
Although the base members of these models cannot be accessed in the controllers, due to ASP proj not referencing the VB projs, they are returned by the controller with JSON result containing all base members.
This is actually great as it fits in with the design of thin controllers.