What’s In This Chapter?
Features of ASP.NET MVC 6
Routing
Creating Controllers
Creating Views
Validating User Inputs
Using Filters
Working with HTML and Tag Helpers
Creating Data-Driven Web Applications
Implementing Authentication and Authorization
Wrox.com Code Downloads for This Chapter
The wrox.com code downloads for this chapter are found at professionalcsharp6 on the Download Code tab. The code for this chapter is divided into the following major examples:
MVC Sample App
Menu Planner
Setting Up Services for ASP.NET MVC 6
Chapter 40, “ASP.NET Core,” showed you the foundation of ASP.NET MVC: ASP.NET Core 1.0 Chapter 40 shows you middleware and how dependency injection works with ASP.NET. This chapter makes use of dependency injection by injecting ASP.NET MVC services.
ASP.NET MVC is based on the MVC (Model-View-Controller) pattern. As shown in Figure 41.1, this standard pattern (a pattern documented in Design Patterns: Elements of Reusable Object-Oriented Software book by the Gang of Four [Addison-Wesley Professional, 1994]) defines a model that implements data entities and data access, a view that represents the information shown to the user, and a controller that makes use of the model and sends data to the view. The controller receives a request from the browser and returns a response. To build the response, the controller can make use of a model to provide some data, and a view to define the HTML that is returned.
Figure 41.1
With ASP.NET MVC, the controller and model are typically created with C# and .NET code that is run server-side. The view is HTML code with JavaScript and just a little C# code for accessing server-side information.
The big advantage of this separation in the MVC pattern is that you can use unit tests to easily test the functionality. The controller just contains methods with parameters and return values that can be covered easily with unit tests.
Let’s start setting up services for ASP.NET MVC 6. With ASP.NET Core 1.0 dependency injection is deeply integrated as you’ve seen in Chapter 40. You can create an ASP.NET MVC 6 project selecting the ASP.NET Core 1.0 Template Web Application. This template already includes NuGet packages required with ASP.NET MVC 6, and a directory structure that helps with organizing the application. However, here we’ll start with the Empty template (similar to Chapter 40), so you can see what’s all needed to build up an ASP.NET MVC 6 project, without the extra stuff you might not need with your project.
The first project created is named MVCSampleApp. To use ASP.NET MVC with the web application MVCSampleApp, you need to add the NuGet package Microsoft.AspNet.Mvc. With the package in place, you add the MVC services by invoking the extension method AddMvc within the ConfigureServices method (code file MVCSampleApp/Startup.cs):
using Microsoft.AspNetCore.Builder; using Microsoft.AspNetCore.Hosting; using Microsoft.AspNetCore.Http; using Microsoft.Extensions.Configuration; using Microsoft.Extensions.DependencyInjection; // etc. namespace MVCSampleApp { public class Startup { // etc. public void ConfigureServices(IServiceCollection services) { services.AddMvc(); // etc. } // etc. public static void Main(string[] args) { var host = new WebHostBuilder() .UseDefaultConfiguration(args) .UseStartup<Startup>() .Build(); host.Run(); } } }
The AddMvc extension method adds and configures several ASP.NET MVC core services, such as configuration features (IConfigureOptions with MvcOptions and RouteOptions); controller factories and controller activators (IControllerFactory, IControllerActivator); action method selectors, invocators, and constraint providers (IActionSelector, IActionInvokerFactory, IActionConstraintProvider); argument binders and model validators (IControllerActionArgumentBinder, IObjectModelValidator); and filter providers (IFilterProvider).
In addition to the core services it adds, the AddMvc method adds ASP.NET MVC services to support authorization, CORS, data annotations, views, the Razor view engine, and more.
Defining Routes
Chapter 40 explains how the Map extension method of the IapplicationBuilder defines a simple route. This chapter shows how the ASP.NET MVC routes are based on this mapping to offer a flexible routing mechanism for mapping URLs to controllers and action methods. The controller is selected based on a route. A simple way to create the default route is to invoke the method UseMvcWithDefaultRoute in the Startup class (code file MVCSampleApp/Startup.cs):