How to delete object which is connected to another model with FK. ASP.NET Core MVC-CodePudding

There is the error: The DELETE statement conflicted with the REFERENCE constraint "FK_ShoppingCartItems_ItemsTable_ItemId". The conflict occurred in database "RandDb", table "dbo.ShoppingCartItems", column 'ItemId'. The statement has been terminated.

Item

public class Item : BaseEntity
    {
        [Required]
        [Display(Name = "Item Photo")]
        public string ItemPhoto { get; set; }
        [Required]
        [Display(Name = "Item Type")]
        public string ItemType { get; set; }
        [Required]
        [Display(Name = "Item Name")]
        public string Name { get; set; }
        [Required]
        [Display(Name = "Item Color")]
        public string Color { get; set; }
        [Required]
        [Display(Name = "Item Size")]
        public string Size { get; set; }
        [Required]
        [Display(Name = "Item Material Type")]
        public string MaterialType { get; set; }
        [Required]
        [Display(Name = "Designed For")]
        public string DesignedFor { get; set; }
        [Required]
        [Display(Name = "Item Price")]
        public double Price { get; set; }
        [Required]
        [Display(Name = "Item Description")]
        public string Description { get; set; }
    }

CartItem

public class CartItem : BaseEntity
    {
        public int? ItemId { get; set; }
        [ForeignKey("ItemId")]
        public Item Item { get; set; }
        public int? UserId { get; set; }
        [ForeignKey("UserId")]
        public User User { get; set; }
        public int Quantity { get; set; }
    }

Repository

public async Task<bool> DeleteAsync(T item)
{
    _entity.Remove(item);
    return await SaveChangesAsync();
}

public async Task<bool> SaveChangesAsync()
        {
            try
            {
                return (await _db.SaveChangesAsync()) >= 0;
            }
            catch
            {
                return false;
            }
        }

I want to do the following: so I have an admin page from where i make crud operations, i also have shopping cart where user can add items, so when any item is added in cart of any user, it doesn't delete, it throws the error which i mentioned above. so what can i do to remove shopping cart items, when admin deletes this item from admin page.

CodePudding user response：

Delete is getting tricky when you have foreign keys, So I don't recomend you to use a generic repository. you can try this code

var cartItems= _entity.Set<CartItem>().Where(i=> i.ItemId == item.Id).ToArray();

    if(cartItems!=null) 
          foreach(var cartItem in cartItems) cartItem.ItemId=null;

    _entity.Set<Item>().Remove(item);

    return await SaveChangesAsync();
}

CodePudding user response：

Adding [Required] would force cascade delete

public class CartItem : BaseEntity
{
    public int? ItemId { get; set; }
    [Required]
    [ForeignKey("ItemId")]
    public Item Item { get; set; }
}

Or using Fluent API you can configure WillCascadeOnDelete(true) to cascade delete.