Çözüldü Sayfa Ekleme Methodu çalışmıyor

    public IActionResult BookDetails(int id)
    {
        var book = _context.Kitaplar
            .Include(b => b.Category)
            .Include(b => b.Pages)
            .FirstOrDefault(b => b.Id == id);

        if (book == null)
            return NotFound();

        return View(book);
    }


    [HttpGet]
    public IActionResult AddBookPage(int bookId)
    {
        var page = new BookPageModel
        {
            BookModelId = bookId
        };

        return View(page);
    }

    [HttpPost]
    public IActionResult AddBookPage(BookPageModel page)
    {
        if (!ModelState.IsValid)
        {
            return View(page);
        }

        if (page.BookModelId == 0)
        {
            ModelState.AddModelError("", "Kitap ID bulunamadı.");
            return View(page);
        }

        _context.BookPages.Add(page);
        _context.SaveChanges();

        return RedirectToAction("BookDetails", new { id = page.BookModelId });
    }

 public class AppDbContext : DbContext
    {
        public AppDbContext(DbContextOptions<AppDbContext> options) : base(options) { }

        public DbSet<UserModel> Kullanicilar { get; set; }
        public DbSet<BookPageModel> BookPages { get; set; }

        public DbSet<BookModel> Kitaplar { get; set; }
        public DbSet<CategoryModel> Kategoriler { get; set; }
        public DbSet<UserBookProgressModel> Kitapİlerlemesi { get; set; }



        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {

 modelBuilder.Entity<BookModel>()
            .HasMany(b => b.KitapSayfasi)
            .WithOne(p => p.BookModel)
            .HasForeignKey(p => p.BookModelId);

        base.OnModelCreating(modelBuilder);


        modelBuilder.Entity<CategoryModel>()
            .HasKey(c => c.Id);



            modelBuilder.Entity<CategoryModel>()
                .HasMany(c => c.SubCategories)
                .WithOne(c => c.ParentCategory)
                .HasForeignKey(c => c.ParentCategoryId);

            base.OnModelCreating(modelBuilder);


        }

    public class BookModel
    {
        public int Id { get; set; }
        public string Title { get; set; } = "";
        public string Author { get; set; } = "";
        public int CategoryId { get; set; }
        public CategoryModel? Category { get; set; }
        public int PageCount { get; set; }
        public int CreatedByUserId { get; set; }
        public UserModel? CreatedByUser { get; set; }
        public byte[]? CoverImage { get; set; }

    public ICollection<BookPageModel> Pages { get; set; } = new List<BookPageModel>();

    }

 public class BookPageModel
  {
    public int Id { get; set; }
    public int BookModelId { get; set; }
    public BookModel? BookModel { get; set; }
    public int PageNumber { get; set; }
    public string Content { get; set; } = string.Empty;

}


}

@model kutuphane.Models.BookModel

<h2>@Model.Title</h2>
<p>Yazar: @Model.Author</p>
<p>Kategori: @Model.Category?.Name</p>
<p>Sayfa Sayısı: @Model.PageCount</p>

<h3>Kitap İçeriği</h3>

@if (Model.Pages != null && Model.Pages.Any())
{
    <ul>
        @foreach(var sayfa in Model.Pages.OrderBy(p => p.PageNumber))
        {
            <li><strong>Sayfa @sayfa.PageNumber:</strong> @sayfa.Content</li>
        }
    </ul>
}
else
{
    <p>Kitap içeriği bulunamadı.</p>
}

<a asp-controller="Home" asp-action="AddBookPage" asp-route-bookId="@Model.Id">Sayfa Ekle</a>

@model kutuphane.Models.BookPageModel
<h2>Sayfa Ekle</h2>
<form asp-action="AddBookPage" method="post">
    <input type="hidden" asp-for="BookModelId" />
    <label for="PageNumber">Sayfa Numarası</label>
    <input asp-for="PageNumber" id="PageNumber" />
    <label for="Content">İçerik</label>
    <textarea asp-for="Content" id="Content"></textarea>
    <button type="submit">Kaydet</button>
</form>