NopCommerce源码分析ContainerBuilder builder.Update(container)

        /// <summary>
        /// Register dependencies
        /// </summary>
        /// <param name="config">Config</param>
        protected virtual void RegisterDependencies(NopConfig config)
        {
            var builder = new ContainerBuilder();
            var container = builder.Build();
            this._containerManager = new ContainerManager(container);

            //we create new instance of ContainerBuilder
            //because Build() or Update() method can only be called once on a ContainerBuilder.

            //dependencies
            var typeFinder = new WebAppTypeFinder();
            builder = new ContainerBuilder();
            builder.RegisterInstance(config).As<NopConfig>().SingleInstance();
            builder.RegisterInstance(this).As<IEngine>().SingleInstance();
            builder.RegisterInstance(typeFinder).As<ITypeFinder>().SingleInstance();
            builder.Update(container);

            //register dependencies provided by other assemblies
            builder = new ContainerBuilder();
            var drTypes = typeFinder.FindClassesOfType<IDependencyRegistrar>();
            var drInstances = new List<IDependencyRegistrar>();
            foreach (var drType in drTypes)
                drInstances.Add((IDependencyRegistrar) Activator.CreateInstance(drType));
            //sort
            drInstances = drInstances.AsQueryable().OrderBy(t => t.Order).ToList();
            foreach (var dependencyRegistrar in drInstances)
                dependencyRegistrar.Register(builder, typeFinder, config);
            builder.Update(container);

            //set dependency resolver
            DependencyResolver.SetResolver(new AutofacDependencyResolver(container));
        }

        #endregion