public void ShowDetailNewItemForm(
    bool animated = false
)

public MainPage() {
    InitializeComponent();
    BindingContext = new TestOrderRepository();
}
private void Button_Clicked(object sender, EventArgs e) {
    grid.ShowDetailNewItemForm();
}

using System.ComponentModel;
namespace GridCrudTestApp;
public abstract class OrderRepository {
   readonly BindingList<Order> orders;
   public OrderRepository() {
       this.orders = new BindingList<Order>();
   }
   public BindingList<Order> Orders {
       get { return orders; }
   }
}
public class TestOrderRepository : OrderRepository {
   const int orderCount = 20;
   readonly Random random;
   public TestOrderRepository() : base() {
       this.random = new Random((int)DateTime.Now.Ticks);
       for (int i = 0; i < orderCount; i++)
           Orders.Add(GenerateOrder(i));
   }
   Order GenerateOrder(int number) {
       Order order = new Order(
           new DateTime(2022, 9, 1).AddDays(random.Next(0, 60)),
           number % 3 == 0,
           RandomProduct(),
           random.Next(1, 100),
           (PackagingType)random.Next(Enum.GetNames(typeof(PackagingType)).Length));
       return order;
   }
   ProductName RandomProduct() {
       Array enumValues = Enum.GetValues(typeof(ProductName));
       return (ProductName)enumValues.GetValue(random.Next(enumValues.Length));
   }
}
public class Order : INotifyPropertyChanged {
   ProductName productName;
   DateTime date;
   bool fastDelivery;
   int quantity;
   PackagingType packagingType;
   public Order() {
       this.productName = ProductName.Tofu;
       this.date = DateTime.Today;
       this.fastDelivery = false;
       this.quantity = 0;
       this.packagingType = PackagingType.CardboardBox;
   }
   public Order(DateTime date, bool fastDelivery, ProductName productName, int quantity, PackagingType packagingType) {
       this.productName = productName;
       this.date = date;
       this.fastDelivery = fastDelivery;
       this.quantity = quantity;
       this.packagingType = packagingType;
   }
   public ProductName ProductName {
       get { return productName; }
       set {
           if (productName != value) {
               productName = value;
               RaisePropertyChanged("ProductName");
           }
       }
   }
   public int Quantity {
       get { return quantity; }
       set {
           if (quantity != value) {
               quantity = value;
               RaisePropertyChanged("Quantity");
           }
       }
   }
   public DateTime Date {
       get { return date; }
       set {
           if (date != value) {
               date = value;
               RaisePropertyChanged("Date");
           }
       }
   }
   public bool FastDelivery {
       get { return fastDelivery; }
       set {
           if (fastDelivery != value) {
               fastDelivery = value;
               RaisePropertyChanged("FastDelivery");
           }
       }
   }
   public PackagingType PackagingType {
       get { return packagingType; }
       set {
           if (packagingType != value) {
               packagingType = value;
               RaisePropertyChanged("PackagingType");
           }
       }
   }
   public event PropertyChangedEventHandler PropertyChanged;
   protected void RaisePropertyChanged(string name) {
       if (PropertyChanged != null)
           PropertyChanged(this, new PropertyChangedEventArgs(name));
   }
}
public enum PackagingType { CardboardBox, CorrugatedBox, ClingFilm, PlasticBox, Chipboard }
public enum ProductName { Tofu, Chocolade, Ikura, Chai, BostonCrabMeat, RavioliAngelo, IponCoffee, QuesoCabrales }