ASP.NET MVC 从IHttp到页面输出

MVCHandler应该算是MVC真正开始的地方。MVCHandler实现了IHttpHandler接口，ProcessRequest便是方法入口。

MVCHandler : IHttpHandler

void IHttpHandler.ProcessRequest(HttpContext httpContext)

{

    this.ProcessRequest(httpContext);

}



protected virtual void ProcessRequest(HttpContext httpContext)

{

    HttpContextBase base2 = new HttpContextWrapper(httpContext);

    this.ProcessRequest(base2);

}



protected internal virtual void ProcessRequest(HttpContextBase httpContext)

{

    IController controller;

    IControllerFactory factory;

    this.ProcessRequestInit(httpContext, out controller, out factory);

    try

    {

        controller.Execute(this.RequestContext);

    }

    finally

    {

        factory.ReleaseController(controller);

    }

}

 

Controller : ControllerBase : IController

void IController.Execute(RequestContext requestContext)  //------>Controller

{

    this.Execute(requestContext);

}



protected virtual void Execute(RequestContext requestContext)   //------>ControllerBase

{

    if (requestContext == null)

    {

        throw new ArgumentNullException("requestContext");

    }

    if (requestContext.HttpContext == null)

    {

        throw new ArgumentException(MvcResources.ControllerBase_CannotExecuteWithNullHttpContext, "requestContext");

    }

    this.VerifyExecuteCalledOnce();

    this.Initialize(requestContext);

    using (ScopeStorage.CreateTransientScope())

    {

        this.ExecuteCore();

    }

}



protected override void ExecuteCore()   //------>Controller

{

    this.PossiblyLoadTempData();

    try

    {

        string requiredString = this.RouteData.GetRequiredString("action");

        if (!this.ActionInvoker.InvokeAction(base.ControllerContext, requiredString))   //public IActionInvoker ActionInvoker { get; set; }

        {

            this.HandleUnknownAction(requiredString);

        }

    }

    finally

    {

        this.PossiblySaveTempData();

    }

}

 

ControllerActionInvoker : IActionInvoker

public virtual bool InvokeAction(ControllerContext controllerContext, string actionName)

{

    if (controllerContext == null)

    {

        throw new ArgumentNullException("controllerContext");

    }

    if (string.IsNullOrEmpty(actionName))

    {

        throw new ArgumentException(MvcResources.Common_NullOrEmpty, "actionName");

    }

    ControllerDescriptor controllerDescriptor = this.GetControllerDescriptor(controllerContext);

    ActionDescriptor actionDescriptor = this.FindAction(controllerContext, controllerDescriptor, actionName);

    if (actionDescriptor == null)

    {

        return false;

    }

    FilterInfo filters = this.GetFilters(controllerContext, actionDescriptor);

    try

    {

        AuthorizationContext context = this.InvokeAuthorizationFilters(controllerContext, filters.AuthorizationFilters, actionDescriptor);

        if (context.Result != null)

        {

            this.InvokeActionResult(controllerContext, context.Result);

        }

        else

        {

            if (controllerContext.Controller.ValidateRequest)

            {

                ValidateRequest(controllerContext);

            }

            IDictionary<string, object> parameterValues = this.GetParameterValues(controllerContext, actionDescriptor);

            ActionExecutedContext context2 = this.InvokeActionMethodWithFilters(controllerContext, filters.ActionFilters, actionDescriptor, parameterValues);

            this.InvokeActionResultWithFilters(controllerContext, filters.ResultFilters, context2.Result);

        }

    }

    catch (ThreadAbortException)

    {

        throw;

    }

    catch (Exception exception)

    {

        ExceptionContext context3 = this.InvokeExceptionFilters(controllerContext, filters.ExceptionFilters, exception);

        if (!context3.ExceptionHandled)

        {

            throw;

        }

        this.InvokeActionResult(controllerContext, context3.Result);

    }

    return true;

}



protected virtual void InvokeActionResult(ControllerContext controllerContext, ActionResult actionResult)

{

    actionResult.ExecuteResult(controllerContext);

}

 

ActionResult

public override void ExecuteResult(ControllerContext context)

{

    if (context == null)

    {

        throw new ArgumentNullException("context");

    }

    if (string.IsNullOrEmpty(this.ViewName))

    {

        this.ViewName = context.RouteData.GetRequiredString("action");

    }

    ViewEngineResult result = null;

    if (this.View == null)

    {

        result = this.FindView(context);   //ViewEngineResult

        this.View = result.View;    //IView接口    

    }

    TextWriter output = context.HttpContext.Response.Output;

    ViewContext viewContext = new ViewContext(context, this.View, this.ViewData, this.TempData, output);

    this.View.Render(viewContext, output);

    if (result != null)

    {

        result.ViewEngine.ReleaseView(context, this.View);

    }

}