How to return the same child List with different condition in the same parent?

Question

User991566988 posted

Hi

I'm calling tow partial views of the same model at a parent one, But I want to call every one with a different condition of the other.

The parent Model:

    public class Mobiles
    {
        public int Id { get; set; }

        public string SerialNo { get; set; }

        public string Notes { get; set; }

        public IList<MobileRuins> MobileRuins { get; set; } = new List<MobileRuins>();
        public IList<MobileRuins> MobileRuins2 { get; set; } = new List<MobileRuins>();

    }

The child MobileRuins class: 

    public class MobileRuins
    {
        public int Id { get; set; }
        
        public int RuinId { get; set; }

        public int MobileId { get; set; }

        public string RuinDetails { get; set; }

        public string Notes { get; set; }

        public Mobiles Mobile { get; set; }
        
        public Ruins Ruin { get; set; }

    }

Including the tow lists in the MobilesController:

    public class MobilesController : Controller
    {
        private readonly ApplicationDbContext _context;

        public MobilesController(ApplicationDbContext context)
        {
            _context = context;
        }
        public async Task<IActionResult> Edit(int? id)
        {
            if (id == null)
            {
                return NotFound();
            }

            var mobiles = await _context.Mobiles
                .Include(n => n.MobileRuins)
                .ThenInclude(m => m.Ruin)
                .Include(n => n.MobileRuins2)
                .ThenInclude(m => m.Ruin)
                .FirstOrDefaultAsync(n => n.Id == id.Value); 
                 mobiles.MobileRuins= mobiles.MobileRuins.Where(c => c.RuinId == 1).ToList();
                 mobiles.MobileRuins2= mobiles.MobileRuins2.Where(c => c.RuinId == 2).ToList();
            if (mobiles == null)
            {
                return NotFound();
            }
            ViewData["RuinId"] = new SelectList(_context.Ruins, "Id", "Ruin");

            return View(mobiles);
        }

The tow partail views ParMobRui and ParMobRui2 with the same model:

@model Mobiles

Calling the tow partial views at Mobiles/Edit view:

            <div class="tab-content">
                <div id="home" class="tab-pane fade in active">
                    @{ await Html.RenderPartialAsync("~/Views/MobileRuins/ParMobRui.cshtml", Model); }
                </div>
                <div id="home" class="tab-pane fade">
                    @{ await Html.RenderPartialAsync("~/Views/MobileRuins/ParMobRui2.cshtml", Model); }
                </div>
            </div>

Now this scenario gives me this error:

InvalidOperationException: Unable to determine the relationship represented by navigation property 'MobileRuins.Mobiles' of type 'Mobiles'. Either manually configure the relationship, or ignore this property using the '[NotMapped]' attribute or by using 'EntityTypeBuilder.Ignore' in 'OnModelCreating'.

When trying to put [NotMapped] like this:

[NotMapped]
public IList<MobileRuins> MobileRuins2 { get; set; } = new List<MobileRuins>();

This gives me this error:

NullReferenceException: Object reference not set to an instance of an object.

How to solve please?

Answer 1

User475983607 posted

Do you actually have a MobileRuins2 entity?

            var mobiles = await _context.Mobiles
                .Include(n => n.MobileRuins)
                .ThenInclude(m => m.Ruin)
                .Include(n => n.MobileRuins2)
                .ThenInclude(m => m.Ruin)
                .FirstOrDefaultAsync(n => n.Id == id.Value); 
                 mobiles.MobileRuins= mobiles.MobileRuins.Where(c => c.RuinId == 1).ToList();
                 mobiles.MobileRuins2= mobiles.MobileRuins.Where(c => c.RuinId == 2).ToList();

Always share the line of code that causes the error when you ask for support on the forums.

Answer 2

User1312693872 posted

Hi,[e-mail]

InvalidOperationException: Unable to determine the relationship represented by navigation property 'MobileRuins.Mobiles' of type 'Mobiles'. Either manually configure the relationship, or ignore this property using the '[NotMapped]' attribute or by using 'EntityTypeBuilder.Ignore' in 'OnModelCreating'.

No need to use [NotMapped], the problem is in your navigation properties, you should add two foreign keys while there are two lists in 'Mobiles':

Model:

 public class MobileRuins
    {
        public int Id { get; set; }
        public int RuinId { get; set; }
        public string RuinDetails { get; set; }
        public string Notes { get; set; }

        public int MobileId_1 { get; set; }
        public Mobiles Mobile { get; set; }
        public int MobileId_2 { get; set; }
        public Mobiles Mobile2 { get; set; }
       ....
}

DbContext to define the foreign key:

protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<Mobiles>().ToTable("Mobiles");
            modelBuilder.Entity<MobileRuins>()
            .HasOne(f => f.Mobile)
            .WithMany(f => f.MobileRuins)
            .HasForeignKey(g => g.MobileId_1);

            modelBuilder.Entity<MobileRuins>()
            .HasOne(f => f.Mobile2)
            .WithMany(f => f.MobileRuins2)
            .HasForeignKey(g => g.MobileId_2);
        }

Then the problem will gone.

Best Regards,

Jerry Cai

Answer 3

User991566988 posted

You are right

Thanks