Xamarin - The type or namespace name 'App' could not be found

Question

Currently getting this error trying to run my Xamarin app to my iPhone live player.

"AppDelegate.cs(1,1): error: The type or namespace name 'App' could not be found (are you missing a using directive or an assembly reference?)"

My solution builds without errors, so slightly stuck. These errors did not occur until after I updated to the most recent update. Any help is greatly appreciated.

App.xaml.cs:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using COCApp;

using Xamarin.Forms;

namespace COCApp
{
    public partial class App : Application
    {
        public App()
        {
            InitializeComponent();
            MainPage = new NavigationPage(new MainPage());
        }

        protected override void OnStart()
        {
            // Handle when your app starts
        }

        protected override void OnSleep()
        {
            // Handle when your app sleeps
        }

        protected override void OnResume()
        {
            // Handle when your app resumes
        }
    }
}

AppDelegate.cs

using System;
using System.Collections.Generic;
using System.Linq;
using COCApp;
using Foundation;
using UIKit;

namespace COCApp.iOS
{
    // The UIApplicationDelegate for the application. This class is responsible for launching the 
    // User Interface of the application, as well as listening (and optionally responding) to 
    // application events from iOS.
    [Register("AppDelegate")]
    public partial class AppDelegate : global::Xamarin.Forms.Platform.iOS.FormsApplicationDelegate
    {
        //
        // This method is invoked when the application has loaded and is ready to run. In this 
        // method you should instantiate the window, load the UI into it and then make the window
        // visible.
        //
        // You have 17 seconds to return from this method, or iOS will terminate your application.
        //
        public override bool FinishedLaunching(UIApplication app, NSDictionary options)
        {
            global::Xamarin.Forms.Forms.Init();
            LoadApplication(new App());

            return base.FinishedLaunching(app, options);
        }
    }
}

Answer 1

It seems like it's because of how you name the project. Mine was called 'Project Name' but in References it was imported as 'Project_Name' which didn't exist so I just deleted that reference and added a correct one by going to Android References->Add Reference->Projects. Now when I create new file namespace is like 'Project Name' and has errors so I ended up recreating the project but this time without spaces in name

Answer 2

I had a similar issue for Android and iOS but mine would build and run just fine except there was a red underline under App on both projects.

I fixed it by right clicking on Android References->Add Reference->Projects then unchecking the already included shared project clicking OK. Then I re-added the shared project and that fixed the error.

Note that PCL is no longer a thing when starting a Xamarin.Forms project in newest Visual Studio version, its .Net Standard now.

Answer 3

Check your project to make sure it has a reference to the PCL.