Wednesday, April 5, 2017

the type 'system Attribute' is defined in an assembly that is not referenced.You must add a reference to assembly 'system.runtime, version=4.0.0.0, culture=neutral, PublickKeyToken=b03f5f7f11d50a3a'



In this error message, {assembly} represents one of the actual files that is found in the "C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.5.2\Facades" folder.

To resolve this problem, install the updated version of the Microsoft .NET Framework 4.5.2 Developer Pack. For download information


https://support.microsoft.com/en-us/help/2901951

During Installation if you get update windows option then update the windows it will resolve your problem.
 

Ensure that this project has Microsoft.Bcl.Build installed and packages.config is located next to the project file

In my Xamarin form application their was dependency Restclient on Microsoft.Bcl.Build Microsoft.Bcl. i just remove all using nuget and ...