第一曲-控制器简介

控制器是维护MVC的灵魂所在，当我们创建一个MVC程序时，vs会自动创建一个Controllers的文件夹，如果你这时候右击它，并移动到Add上，便会看见Controller，点击它，并取名为HomeController，确定之后你会看见这样的页面。

public class HomeController : Controller
    {
        // GET: Home
        public ActionResult Index()
        {
            return View();
        }
    }

是的，一个继承了Controller类的对象，并且里面有一个公共方法，这个方法返回一个ActionResult类。我们选中ActionResult，点击F12，也就是查看定义。可以看到这个类的定义。

// Summary:
    //     Represents the result of an action method.
    public abstract class ActionResult {
        // Summary:
        //     Initializes a new instance of the System.Web.Mvc.ActionResult class.
        protected ActionResult();

        // Summary:
        //     Enables processing of the result of an action method by a custom type that
        //     inherits from the System.Web.Mvc.ActionResult class.
        //
        // Parameters:
        //   context:
        //     The context in which the result is executed. The context information includes
        //     the controller, HTTP content, request context, and route data.
        public abstract void ExecuteResult(ControllerContext context);
    }

这货是一个抽象方法，本身并不能被实例化。也就是说，我们必须返回继承他的子类。这时候我们可以看到自动生成的这个方法返回了一个View()。OK，我们看一下这个View()的定义

//
        // Summary:
        //     Creates a System.Web.Mvc.ViewResult object that renders a view to the response.
        //
        // Returns:
        //     The System.Web.Mvc.Controller.View() result that renders a view to the response.
        protected internal ViewResult View();

这个View方法返回一个ViewResult类，好吧，我们继续探究这个ViewResult类，我们经过两次F12后，终于看到了尽头，这个类果然是继承了ActionResult的。

// Summary:
    //     Represents a class that is used to render a view by using an System.Web.Mvc.IView
    //     instance that is returned by an System.Web.Mvc.IViewEngine object.
    public class ViewResult:ViewResultBase {
        // Summary:
        //     Initializes a new instance of the System.Web.Mvc.ViewResult class.
        public ViewResult();

        // Summary:
        //     Gets the name of the master view (such as a master page or template) to use
        //     when the view is rendered.
        //
        // Returns:
        //     The name of the master view.
        public string MasterName { get; set; }

        // Summary:
        //     Searches the registered view engines and returns the object that is used
        //     to render the view.
        //
        // Parameters:
        //   context:
        //     The controller context.
        //
        // Returns:
        //     The object that is used to render the view.
        //
        // Exceptions:
        //   System.InvalidOperationException:
        //     An error occurred while the method was searching for the view.
        protected override ViewEngineResult FindView(ControllerContext context);
    }
}

// Summary:
    //     Represents a base class that is used to provide the model to the view and
    //     then render the view to the response.
    public abstract class ViewResultBase:ActionResult {
        // Summary:
        //     Initializes a new instance of the System.Web.Mvc.ViewResultBase class.
        protected ViewResultBase();

        // Summary:
        //     Gets the view data model.
        //
        // Returns:
        //     The view data model.
        public object Model { get; }
        //
        // Summary:
        //     Gets or sets the System.Web.Mvc.TempDataDictionary object for this result.
        //
        // Returns:
        //     The temporary data.
        public TempDataDictionary TempData { get; set; }
        //
        // Summary:
        //     Gets or sets the System.Web.Mvc.IView object that is rendered to the response.
        //
        // Returns:
        //     The view.
        public IView View { get; set; }
        //
        // Summary:
        //     Gets the view bag.
        //
        // Returns:
        //     The view bag.
        [Dynamic]
        public dynamic ViewBag { get; }
        //
        // Summary:
        //     Gets or sets the view data System.Web.Mvc.ViewDataDictionary object for this
        //     result.
        //
        // Returns:
        //     The view data.
        public ViewDataDictionary ViewData { get; set; }
        //
        // Summary:
        //     Gets or sets the collection of view engines that are associated with this
        //     result.
        //
        // Returns:
        //     The collection of view engines.
        public ViewEngineCollection ViewEngineCollection { get; set; }
        //
        // Summary:
        //     Gets or sets the name of the view to render.
        //
        // Returns:
        //     The name of the view.
        public string ViewName { get; set; }

        // Summary:
        //     When called by the action invoker, renders the view to the response.
        //
        // Parameters:
        //   context:
        //     The context that the result is executed in.
        //
        // Exceptions:
        //   System.ArgumentNullException:
        //     The context parameter is null.
        public override void ExecuteResult(ControllerContext context);
        //
        // Summary:
        //     Returns the System.Web.Mvc.ViewEngineResult object that is used to render
        //     the view.
        //
        // Parameters:
        //   context:
        //     The context.
        //
        // Returns:
        //     The view engine.
        protected abstract ViewEngineResult FindView(ControllerContext context);
    }

并且在途中还看到了一些奇奇怪怪的属性和方法，欧，饶了我吧，这么多东西，怎么学啊！！！！！！！！额。。。现在我告诉你一件听了你可能会生气的事情，就是我们看了这么多东西，其实，这些东西并没有什么卵用（尼玛！！坑爹啊！(╯°口°)╯(┴—┴

好吧，是暂时没什么卵用，不代表以后没用。（￣▽￣）

我们再回到HomeController类中，在Index方法下右击Add View，直接确定，什么都不用看。你会来到一个cshtml页面。这特么又是什么鬼啊？？在这里，我要很高兴地告诉你，你来到了第二曲的地方-视图（就是MVC中的View啦），下一曲开始！

----来自《吹响！上低音号》