I am trying to delete some category using ASP.NET Core and Entity Framework Core. When I click “delete”, it shows an error

This page isn’t working. If the problem continues, contact the site owner. HTTP ERROR 405

If I try to debug, it never hits the breakpoint I set. It never goes to the controller. Why is that?

Here is my code – this is controller:

using Microsoft.AspNetCore.Mvc;
using practiceBookstore.Data;
using practiceBookstore.Data.Repository.IRepository;
using practiceBookstore.Models;

namespace practiceBookstore.Controllers
{
    public class CategoryController : Controller
    {
        private readonly ICategoryRepository _categoryRepository;

        public CategoryController(ICategoryRepository categoryRepository)
        {
            _categoryRepository = categoryRepository;
        }

        public IActionResult Index()
        {
            List<Category> Categories = _categoryRepository.GetAll().ToList();
            return View(Categories);
        }

        public IActionResult Create()
        {
            return View();
        }

        [HttpPost]
        public IActionResult Create(Category category)
        {
            if (category == null)
            {
                return NotFound();
            }

            if (ModelState.IsValid)
            {
                _categoryRepository.Add(category);
                _categoryRepository.Save();
                return RedirectToAction("Index");
            }

            return View(category);
        }

        public IActionResult Edit(int? id)
        {
            if (id == null || id == 0)
            {
                return NotFound();
            }

            Category? category= _categoryRepository.Get(u => u.CategoryId == id);

            if (category == null)
            {
                return NotFound();
            }

            return View(category);
        }

        [HttpPost]
        public IActionResult Edit(Category category)
        {
            if (category == null)
            {
                return NotFound();
            }

            if (ModelState.IsValid)
            {
                _categoryRepository.Update(category);
                _categoryRepository.Save();
                return RedirectToAction("Index");
            }

            return View(category);
        }

        [HttpPost]
        public IActionResult Delete(int? id)
        {
            if (id == 0 || id == null)
            {
                return NotFound();
            }

            Category ?category= _categoryRepository.Get(c => c.CategoryId == id);

            if (category == null)
            {
                return NotFound();
            }

            _categoryRepository.Remove(category);
            _categoryRepository.Save();

            return RedirectToAction("Index");
        }
    }
}

This is index page of category, where the edit and delete buttons are:

@model List<Category>

<h1>Category List</h1>
<a asp-action="Create" asp-controller="Category" class="btn bg-dark text-white">Create new Category</a>
<table class="table table-bordered table-striped">
    <thead>
        <tr>
            <th>Name</th>
            <th>Display Order</th>
            <th></th>
        </tr>
    </thead>
    <tbody>
        @foreach(var i in Model)
        {
            <tr>
                <td>@i.Name</td>
                <td>@i.DisplayOrder</td>
                <td>
                    <a asp-action="Edit" asp-controller="Category" asp-route-id="@i.CategoryId" class="btn btn-success">Edit</a>
                    <a asp-controller="Category" asp-action="Delete" asp-route-id="@i.CategoryId" class="btn btn-danger">Delete</a>
                </td>
            </tr>
        }
    </tbody>
</table>

I use repository pattern for database.

Here is IRepository:

using System.Linq.Expressions;

namespace practiceBookstore.Data.Repository.IRepository
{
    public interface IRepository<T> where T : class
    {
        IEnumerable<T> GetAll();
        T Get(Expression<Func<T, bool>> filter);
        void Add(T entity);
        void Remove(T entity);
        void RemoveRange(IEnumerable<T> entities);
    }
}

Here is the implementation:

using Microsoft.EntityFrameworkCore;
using practiceBookstore.Data.Repository.IRepository;
using System.Linq.Expressions;

namespace practiceBookstore.Data.Repository
{
    public class Repository<T> : IRepository<T> where T : class
    {
        private readonly ApplicationDbContext _db;
        internal DbSet<T> Dbset;

        public Repository(ApplicationDbContext db)
        {
            _db = db;
            this.Dbset = _db.Set<T>();
        }

        public void Add(T entity)
        {
            Dbset.Add(entity);
        }

        public T Get(Expression<Func<T, bool>> filter)
        {
            IQueryable<T> query = Dbset.Where(filter);
            return query.FirstOrDefault();
        }

        public IEnumerable<T> GetAll()
        {
            IQueryable<T> query = Dbset;
            return query.ToList();
        }

        public void Remove(T entity)
        {
            Dbset.Remove(entity);
        }

        public void RemoveRange(IEnumerable<T> entities)
        {
            Dbset.RemoveRange(entities);
        }
    }
}

This is ICategoryRepository:

using practiceBookstore.Models;

namespace practiceBookstore.Data.Repository.IRepository
{
    public interface ICategoryRepository : IRepository<Category>
    {
        void Update(Category category);
        void Save();
    }
}

This is implementation:

using practiceBookstore.Data.Repository.IRepository;
using practiceBookstore.Models;
using System.Linq.Expressions;

namespace practiceBookstore.Data.Repository
{
    public class CategoryRepository : Repository<Category>, ICategoryRepository
    {
        private readonly ApplicationDbContext _db;

        public CategoryRepository(ApplicationDbContext db) : base(db)
        {
            _db = db;
        }

        public void Save()
        {
            _db.SaveChanges();
        }

        public void Update(Category category)
        {
            _db.Update(category);
        }
    }
}

When I click delete, I expected it the code to delete the category and redirect to the index page.