Hiện em đang viết một cái API theo hướng dẫn của một trang web. Khi test API trên swagger UI em có gặp phải một lỗi như ở dưới đây. Mn giúp em với. Em cảm ơn ạ.
CategoriesController.cs
using Microsoft.AspNetCore.Mvc;
using Supermarket.API.Domain.Models;
using Supermarket.API.Domain.Services;
namespace Supermarket.API.Controllers
{
[Route("/api/[controller]")]
public class CategoriesController : Controller
{
private readonly ICategoryService? _categoryService; //a private, read-only field to access the methods of our category service implementation
public CategoriesController(ICategoryService categoryService)
{
_categoryService = categoryService; //receives an instance of ICategoryService
}
// Create a category service to return all categories
[HttpGet] // tells the ASP.NET Core pipeline to use it to handle GET requests
public async Task<IEnumerable<Category>> GetAllAsync(ICategoryService _categoryService)
{
var categories = await _categoryService.ListAsync();
return categories;
}
}
}
Category.cs
namespace Supermarket.API.Domain.Models
{
public class Category
{
public int Id { get; set; }
public string? Name { get; set; }
public IList<Product>? Products { get; set; } = new List<Product>();
}
}
EUnitOfMeasurement.cs
using System.ComponentModel;
namespace Supermarket.API.Domain.Models
{
public enum EUnitOfMeasurement : byte
{
[Description("UN")]
Unity = 1,
[Description("MG")]
Milligram = 2,
[Description("G")]
Gram = 3,
[Description("KG")]
Kilogram = 4,
[Description("L")]
Liter = 5
}
}
Product.cs
namespace Supermarket.API.Domain.Models
{
public class Product
{
public int Id { get; set; }
public string? Name { get; set; }
public short QuantityInPackage { get; set; }
public EUnitOfMeasurement UnitOfMeasurement { get; set; }
public int CategoryId { get; set; }
public Category? Category { get; set; }
}
}
AppDbContext.cs
using Microsoft.EntityFrameworkCore;
using Supermarket.API.Domain.Models;
namespace Supermarket.API.Domain.Persistence.Contexts
{
// DbContext is a class EF Core uses to map your models to database tables
// implement the database context class first
public class AppDbContext : DbContext
{
public DbSet<Category> Categories { get; set; }
public DbSet<Product> Products { get; set; }
// constructor passes the database configuration to the base class through dependency injection
public AppDbContext(DbContextOptions<AppDbContext> options) : base(options) { }
// OnModelCreating map the models’ properties to the respective table columns
// specifying which properties are primary keys, which are foreign keys, the column types, etc
protected override void OnModelCreating(ModelBuilder builder)
{
base.OnModelCreating(builder);
builder.Entity<Category>().ToTable("Categories");
builder.Entity<Category>().HasKey(p => p.Id); // Set the primary key
builder.Entity<Category>().Property(p => p.Id).IsRequired().ValueGeneratedOnAdd();
builder.Entity<Category>().Property(p => p.Name).IsRequired().HasMaxLength(30);
builder.Entity<Category>().HasMany(p => p.Products).WithOne(p => p.Category).HasForeignKey(p => p.CategoryId);
// add two example categories by default
builder.Entity<Category>().HasData
(
new Category { Id = 100, Name = "Fruits and Vegetables" }, // Id set manually due to in-memory provider
new Category { Id = 101, Name = "Dairy" }
);
builder.Entity<Product>().ToTable("Products");
builder.Entity<Product>().HasKey(p => p.Id);
builder.Entity<Product>().Property(p => p.Id).IsRequired().ValueGeneratedOnAdd();
builder.Entity<Product>().Property(p => p.Name).IsRequired().HasMaxLength(50);
builder.Entity<Product>().Property(p => p.QuantityInPackage).IsRequired();
builder.Entity<Product>().Property(p => p.UnitOfMeasurement).IsRequired();
}
}
}
BaseRepository.cs
using Supermarket.API.Domain.Persistence.Contexts;
namespace Supermarket.API.Domain.Persistence.Repositories
{
public abstract class BaseRepository
{
protected readonly AppDbContext _context;
// receives an instance of our AppDbContext through dependency injection and exposes a protected property
// _context gives access to all methods we need to handle database operations.
public BaseRepository(AppDbContext context)
{
_context = context;
}
}
}
CategoryRepository.cs
using Microsoft.EntityFrameworkCore;
using Supermarket.API.Domain.Models;
using Supermarket.API.Domain.Persistence.Contexts;
using Supermarket.API.Domain.Repositories;
namespace Supermarket.API.Domain.Persistence.Repositories
{
// The repository inherits the BaseRepository and implements ICategoryRepository.
public class CategoryRepository : BaseRepository, ICategoryRepository
{
public CategoryRepository(AppDbContext context) : base(context)
{
}
public async Task<IEnumerable<Category>> ListAsync()
{
return await _context.Categories.ToListAsync();
// ToListAsync transforms the result of a query into a collection of categories.
}
}
}
ICategoryRepository.cs
using Supermarket.API.Domain.Models;
namespace Supermarket.API.Domain.Repositories
{
public interface ICategoryRepository
{
Task<IEnumerable<Category>> ListAsync();
}
}
ICategoryService.cs
using Supermarket.API.Domain.Models;
namespace Supermarket.API.Domain.Services
{
// defines methods to handle some business logic
// isolate the request and response handling from the real logic needed to complete tasks
// this method returns all existing categories in the database.
public interface ICategoryService
{
Task<IEnumerable<Category>> ListAsync();
// wait for the database to complete some operation to return the data
}
}
CategoryService.cs
using Supermarket.API.Domain.Models;
using Supermarket.API.Domain.Repositories;
using Supermarket.API.Domain.Services;
namespace Supermarket.API.Services
{
public class CategoryService : ICategoryService
{
private readonly ICategoryRepository _categoryRepository;
public CategoryService(ICategoryRepository categoryRepository)
{
_categoryRepository = categoryRepository;
}
// using an instance of ICategoryRepository to return the data.
public async Task<IEnumerable<Category>> ListAsync()
{
return await _categoryRepository.ListAsync();
}
}
}
Program.cs
using Microsoft.EntityFrameworkCore;
using Supermarket.API.Domain.Persistence.Contexts;
using Supermarket.API.Domain.Services;
using Supermarket.API.Services;
using Supermarket.API.Domain.Repositories;
using Supermarket.API.Domain.Persistence.Repositories;
var builder = WebApplication.CreateBuilder(args);
// Add services to the container.
builder.Services.AddControllers();
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();
builder.Services.AddDbContext<AppDbContext>(opt =>
opt.UseSqlServer(builder.Configuration.GetConnectionString("Connect")));
builder.Services.AddScoped<ICategoryRepository, CategoryRepository>();
builder.Services.AddScoped<ICategoryService, CategoryService>();
var app = builder.Build();
// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
app.UseDeveloperExceptionPage();
app.UseSwagger();
app.UseSwaggerUI();
}
app.UseHttpsRedirection();
app.UseAuthorization();
app.MapControllers();
app.Run();
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