AppDelegate.cs

using System;
using System.Collections.Generic;
using System.Linq;
using MonoTouch.Foundation;
using MonoTouch.UIKit;
using Xamarin.Forms;

namespace SG.iOS {  
  [Register("AppDelegate")]
  public partial class AppDelegate : UIApplicationDelegate {
    UIWindow window;
    public override bool FinishedLaunching(UIApplication app, NSDictionary options) {
      Forms.Init();
      window = new UIWindow(UIScreen.MainScreen.Bounds);
      window.RootViewController = App.GetMainPage().CreateViewController(); 
      window.MakeKeyAndVisible();
      return true;
    }
  }
}