Do you get a 404 error when adding a category?

Question

ASP.NET

public void ConfigureServices(IServiceCollection services)
        {
            services.AddRazorPages();
            services.AddMvc();
           
            services.AddTransient<IRepository, DataRepository>();
            services.AddTransient<ICategoryRepository, CategoryRepository>();
            string conString = Configuration["ConnectionStrings:DefaultConnection"];
            services.AddDbContext<DataContext>(options =>
            options.UseSqlServer(conString));
            
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseExceptionHandler("/Error");
                // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
                app.UseHsts();
            }
            
            app.UseHttpsRedirection();
            app.UseStaticFiles();

            app.UseRouting();

            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllerRoute(
                    name: "default",
                    pattern: "{controller=Home}/{action=Index}/{id?}");
                endpoints.MapControllerRoute(
                  name: "default",
                  pattern: "{controller=Categories}/{action=Index}/{id?}");
            });
           
        }

@model Category
<div class="row p-2">
    <div class="col-1"></div>
    <div class="col">
        <input asp-for="Name" class="form-control" />
    </div>
    <div class="col">
        <input asp-for="Description" class="form-control" />
    </div>
    <div class="col-3">
       @if (Model.Id == 0)
        {
            <button type="submit" class="btn btn-primary">Add</button>
        }
        else
        {
            <button type="submit" class="btn btn-outline-primary">Save</button>
            <a asp-action="Index" class="btn btn-outline-secondary">Cancel</a>
        }
    </div>
</div>

@model IEnumerable<Category>

<h3 class="p-2 bg-primary text-white text-center">Categories</h3>

<div class="container-fluid mt-3">
    <div class="row">
        <div class="col-1 font-weight-bold">Id</div>
        <div class="col font-weight-bold">Name</div>
        <div class="col font-weight-bold">Description</div>
        <div class="col-3"></div>
    </div>
    @if (ViewBag.EditId == null)
    {
        <form asp-action="AddCategory" method="post">
            @Html.Partial("CategoryEditor", new Category())
        </form>
    }
    @foreach (Category c in Model)
    {
        @if (c.Id == ViewBag.EdiId)
        {
            <form asp-action="UpdateCategory" method="post">
                <input type="hidden" name="Id" value="@c.Id" />
                @Html.Partial("CategoryEditor", c)
            </form>
        }
        else
        {
            <div class="row p-2">
                <div class="col-1">@c.Id</div>
                <div class="col">@c.Name</div>
                <div class="col">@c.Description</div>
                <div class="col-3">
                    <form asp-action="DeleteCategory" method="post">
                        <input type="hidden" name="Id" value="@c.Id" />
                        <a asp-action="EditCategory" asp-route-id="@c.Id" class="btn btn-outline-primary">Edit</a>
                        <button type="submit" class="btn btn-outline-danger">Delete</button>
                    </form>
                </div>
            </div>
        }
    }
</div>

public interface ICategoryRepository
    {
        IEnumerable<Category> Categories { get; }
        void AddCategory(Category category);
        void UpdateCategory(Category category);
        void DeleteCategory(Category category);
    }

public class CategoryRepository : ICategoryRepository
    {
        private DataContext context;
        public CategoryRepository(DataContext ctx) => context = ctx;
        public IEnumerable<Category> Categories => context.Categories;

        public void AddCategory(Category category)
        {
            context.Categories.Add(category);
            context.SaveChanges();
        }

        public void UpdateCategory(Category category)
        {
            context.Categories.Update(category);
            context.SaveChanges();
        }
        public void DeleteCategory(Category category)
        {
            context.Categories.Remove(category);
            context.SaveChanges();
        }

    }

public class CategoriesContoller : Controller
    {
        private ICategoryRepository repository;
        public CategoriesContoller(ICategoryRepository repo)
        {
            repository = repo;
        }
        public IActionResult Index() => View(repository.Categories);

        [HttpPost]
        public IActionResult AddCategory(Category category)
        {
            repository.AddCategory(category);
            return RedirectToAction(nameof(Index));
        }
        public IActionResult EditCategory(long id)
        {
            ViewBag.EditId = id;
            return View("Index", repository.Categories);
        }

        [HttpPost]
        public IActionResult UpdateCategory(Category category)
        {
            repository.UpdateCategory(category);
            return RedirectToAction(nameof(Index));
        }

        [HttpPost]
        public IActionResult DeleteCategory(Category category)
        {
            repository.DeleteCategory(category);
            return RedirectToAction(nameof(Index));
        }
    }

Answer 1

Stop repeating the same question