Error: Could not resolve type with token 01000041

Reading the SOen , I understood that this problem refers to different package versions. The whole point is that for example, my project I installed everything. But the classes I'm migrating from another project. What happens when I call MainPage, just at the moment of loading the call to InitializeComponents I get this error:

  

Could not resolve type with token 01000041 (from typeref,   class / assembly Xamarin.Forms.Internals.ResourceLoader,   Xamarin.Forms.Core, Version = 2.0.0.0, Culture = neutral,   PublicKeyToken = null)

My code in xaml, I put a try..catch to catch Exception

[XamlCompilation(XamlCompilationOptions.Compile)]
    public partial class MainPage : ContentPage
    {
        DataService dataService;
        public MainPage()
        {
            try
            {
                InitializeComponent();
            }
            catch(Exception ex)
            {
                string err = ex.Message;
            }
            NavigationPage.SetHasNavigationBar(this, false);
            dataService = new DataService();
        } 
   }