The type 'Attribute' is defined in an assembly that is not referenced - Xamarin

3
votes

After I upgraded the Xamarin.Forms version in my Xamarin Forms PCL project from 2.x to 3.x I got the following error message which prevent me from building the UWP project.

The type 'Attribute' is defined in an assembly that is not referenced. You must add a reference to assembly 'netstandard, Version=2.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51'

The strange thing about this is that I could build the Android and iOS projects.

Any ideas what I could do to get the UWP project working, too?

1
c#xamarinxamarin.formsuwpvisual-studio-2017
I take it you did this: You must add a reference to assembly 'netstandard? :) – Gerald Versluis
But netstandard isn't a nuget package how should I add it? – Genfood
nuget.org/packages/NETStandard.Library – Hans Passant
@HansPassant I have this one already installed :( – Genfood

1 Answers

6
votes

In this case I changed the min version of the UWP SDK to 1709 (Fall Creators Update) Build 16299 and I was able to build my UWP project again.

Previously I used a lower UWP SDK version.

As you see here in this version Microsoft added .NET Standard 2.0 support for Windows.