SamusevWinApp/Product.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.ComponentModel.DataAnnotations;
using Microsoft.EntityFrameworkCore;

namespace samusev_42;

public partial class Product : IEditableObject
{
    private Ispr2522SamusevOvLazarev2Context context;

    public int IdProduct { get; set; }
    public string Article { get; set; } = null!;
    public int IdProductName { get; set; }
    public string Unit { get; set; } = null!;
    public decimal Price { get; set; }
    public int IdSupplier { get; set; }
    public int IdManufacturer { get; set; }
    public int IdCategory { get; set; }
    public int Discount { get; set; }
    public int Count { get; set; }
    public string Description { get; set; } = null!;
    public string Photo { get; set; } = null!;

    public virtual Category IdCategoryNavigation { get; set; } = null!;
    public virtual Manufacturer IdManufacturerNavigation { get; set; } = null!;
    public virtual ProductName IdProductNameNavigation { get; set; } = null!;
    public virtual Supplier IdSupplierNavigation { get; set; } = null!;
    public virtual ICollection<OrdersProduct> OrdersProducts { get; set; } = new List<OrdersProduct>();

    // Реализация валидации IEditableObject

    public void BeginEdit()
    {
        if (context == null)
        {
            context = new Ispr2522SamusevOvLazarev2Context();
            context.Products.Attach(this); 
        }
    }

    public void CancelEdit()
    {
        if (context != null)
        {
            var entry = context.Entry(this);
            if (entry.State == EntityState.Modified)
            {
                entry.Reload(); 
            }
        }
    }

    public void EndEdit()
    {
        // ВАЛИДАЦИЯ
        if (string.IsNullOrWhiteSpace(this.Article))
        {
            throw new ValidationException("Артикул не может быть пустым!");
        }

        if (this.Price < 0)
        {
            throw new ValidationException("Цена не может быть отрицательной!");
        }

        if (context != null)
        {
            context.SaveChanges();
        }
    }
}