Relacionamento Many-to-Many no Entity Framework 3.1 (EF Core 3.1)

dotnet-efcore-3.1-many-to-many-map.cs

namespace Example.Dotnet
{
    public class DatabaseContext : DbContext
    {
        public DatabaseContext(DbContextOptions<DatabaseContext> options) : base(options)
        {
        }
        
        #region --- DBSets ---
        public DbSet<Product> Products { get; set; }
        public DbSet<Category> Categories { get; set; }
        public DbSet<ProductCategory> ProductCategories { get; set; }
        #endregion

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<ProductCategory>()
                .HasKey(productCategory => new { productCategory.ProductId, productCategory.CategoryId });

            modelBuilder.Entity<ProductCategory>()
                .HasOne(productCategory => productCategory.Product)
                .WithMany(product => product.ProductCategories)
                .HasForeignKey(productCategory => productCategory.ProductId); 

            modelBuilder.Entity<ProductCategory>()
                .HasOne(productCategory => productCategory.Category)
                .WithMany(category => category.ProductCategories)
                .HasForeignKey(productCategory => productCategory.CategoryId);
                
            base.OnModelCreating(modelBuilder);
        }
    }
}