You must add a reference to assembly mscorlib, version=4.0.0

Question

I\'m having some trouble migrating a web project from RC1 to RC2. When I switched, I\'m getting a bunch of these errors throughout the project.

The ty

Answer 1

I had the same issue and adding the following package to my project.json dependencies fixed it for me:

"Microsoft.NETCore.Portable.Compatibility": "1.0.1-rc2-24027",

This package enables compatibility with mscorlib-based PCLs.

Answer 2

In fact, the problem is an old lib that requires an asp.net 4.0 or 4.5 vesion (less than Core).

Microsoft provides a solution for it by installing the fallowing NuGet package.

Microsoft.NETCore.Portable.Compatibility

this way you will be able to run your code with old libs.

Answer 3

I don't have the rep to comment but Matt Kemp's post lead to my solution . In my case it was using a Class Library(.Net Standard) instead of Android Class Library (Xamarin)

Answer 4

I got this error when I created a new project using the template Class Library (.NET Standard) and ported some code into it that I wanted to re-use.

I created a new project Class Library (.NET Framework) and moved the code there instead and it worked without any issues.