I have two tables - Order and MenuItem with many-to-many relation.

 public class Order
    {
        [Key]
        public int OrderId { get; set; }
        public DateTime OrderDate { get; set; }
        public string Comments { get; set; }
        public string OrderStatus { get; set; }
        public string WaiterName { get; set; }
        public double TotalPrice { get; set; }

        public virtual ICollection<MenuItem> MenuItems { get; set; }
    }

 public class MenuItem
    {
        [Key]
        public int MenuItemId { get; set; }

        public string Name { get; set; }
        public double Price { get; set; }

        public int MenuItemTypeId { get; set; }
        public MenuItemType MenuItemType { get; set; }

        public virtual ICollection<Order> Orders { get; set; }
    }

public class OrderMenuItem
    {
        public int MenuItemId { get; set; }
        public int OrderId { get; set; }

        public Order Order { get; set; }
        public MenuItem MenuItem { get; set; }
    }

modelBuilder.Entity<MenuItem>()
                .HasMany(m => m.Orders)
                .WithMany(o => o.MenuItems)
                .UsingEntity<OrderMenuItem>(
                x => x.HasOne(x => x.Order)
                .WithMany().HasForeignKey(x => x.OrderId),
                x => x.HasOne(x => x.MenuItem)
                .WithMany().HasForeignKey(x => x.MenuItemId)
                );

The question is how can I retrieve MenuItems that are in certain order and show the data using the ListView?

CodePudding user response：

Just use the navigation property.

The simple and easy way would be

var order = await _context.Orders
    .Where(o => ...)
    .Include(o => o.MenuItems)
    .FirstOrDefaultAsync();

and the proper way would be, one that also lets you filter and order the items would be

var order = await _context.Orders
    .Where(o => ...)
    .Select(o => new OrderDto {
        Id = o.Id,
        Status = o.Status,
        // etc
        Items = o.Items
            .Where(i => ...)
            .OrderBy(i => ...)
            // etc
    })
    .FirstOrDefaultAsync();

And while we're at it, delete that virtual modifier. It's used for lazy loading, and what you want here is not lazy loading.

CodePudding user response：

Just to tack on to what Angius posted:

var orderedMenuItems = dbContext.MenuItems.OrderBy(mi => mi.id).ToList();

Then just connect your list to your UI.