使用DI

Unit

參考的文章

• http://netmvc.blogspot.tw/2012/04/dependency-injection-in-aspnet-mvc-4.html
• http://stackoverflow.com/questions/17460475/dependency-injection-in-asp-net-web-api-using-unity-error
• http://benfoster.io/blog/per-request-dependencies-in-aspnet-web-api-using-structuremap

var container = BuildUnityContainer(); 

DependencyResolver.SetResolver(new UnityDependencyResolver(container)); 

GlobalConfiguration.Configuration.DependencyResolver = new Unity.WebApi.UnityDependencyResolver(container); 

return container;

HierarchicalLifetimeManager

http://www.asp.net/web-api/overview/advanced/dependency-injection

public static void Register(HttpConfiguration config)
{
    var container = new UnityContainer();
    container.RegisterType<IProductRepository, ProductRepository>(new HierarchicalLifetimeManager());
    config.DependencyResolver = new UnityResolver(container);

    // Other Web API configuration not shown.
}