agrobot_base/AgroBase/OperationControl/App.xaml.cs

using OperationControl.Models;
using System.Windows;
using Application = System.Windows.Application;

namespace OperationControl
{
    /// <summary>
    /// Interaction logic for App.xaml
    /// </summary>
    public partial class App : Application
    {
        public AppShell Shell { get; private set; }

        private void Application_Startup(object sender, StartupEventArgs e)
        {
            // Cria o “controlador”/janela raiz
            Shell = new AppShell();
            Shell.Inicializar();
        }

    }

}