C# VS2017 IStringable Unreferenced Exception using Windows.Data.Json
This error is showing up everywhere I use the JsonObject, however, NOT in the UWP app project.
The Windows.Foundation.FoundationContract assembly is platform specific. You could not use it in your portable library. It will throw compiling error, though you can add the reference via pick winmd file where in the below folder.
C:\Program Files (x86)\Windows Kits\10\References\Windows.Foundation.FoundationContract\2.0.0.0\Windows.Foundation.FoundationContract.winmdCurrently,Json.NET has supported portable library, you could use it to parse json. You could chose Json.NET which does not cause complex assembly dependencies.