傻瓜教你看清MVC内部执行流程之ViewData数据传输,轻松学MVC--①目了然篇(待续)

1.首先在执行到Controller里面的action(方法)时,执行到最后会调用一个View()-->此方法是Controller的一个方法

源代码:

protected internal ViewResult View(){return View(null /* viewName */, null /* masterName */, null /* model */);}

 

 2.然后继续调用自己的View(参数1,参数2,参数3)带三个参数的view()   

    

 protected internal virtual ViewResult View(string viewName, string masterName, object model){if (model != null) {ViewData.Model = model;}return new ViewResult {ViewName = viewName,MasterName = masterName,ViewData = ViewData,TempData = TempData};}

 

 3.在上步View(string viewName, string masterName, object model)执行完毕将数据封装到ViewResult(ActionResult的子类)中以后MVC会自己调用ViewResult的父类ViewResultBase的ExecuteResult(),方法里面会封装好viewContext对象,并调用IView接口的Render()方法

   

      public override void ExecuteResult(ControllerContext context){if (context == null) {throw new ArgumentNullException("context");}//其中会判断View()是否有action名,没有则会默认将"路由里面"的action赋值给ViewNameif (String.IsNullOrEmpty(ViewName)) {ViewName = context.RouteData.GetRequiredString("action");}ViewEngineResult result = null;if (View == null) {result = FindView(context);View = result.View;}TextWriter writer = context.HttpContext.Response.Output;//封装数据到viewContext上下文中
ViewContext viewContext = new ViewContext(context, View, ViewData, TempData, writer);View.Render(viewContext, writer);//调用IView接口的Render()方法if (result != null) {result.ViewEngine.ReleaseView(context, View);}}

 未完待续...

 4.而IView接口是由BuildManagerCompiledView类实现的,此类乃是一个抽象类,最终是有WebFormView类来继承并重写了RenderView方法,最终完成ViewData赋值给ViewPage类的ViewData字典属性,最后完成输出显示

  

      public void Render(ViewContext viewContext, TextWriter writer) {if (viewContext == null) {throw new ArgumentNullException("viewContext");}object instance = null;Type type = BuildManager.GetCompiledType(ViewPath);if (type != null) {instance = _viewPageActivator.Create(_controllerContext, type);}if (instance == null) {throw new InvalidOperationException(String.Format(CultureInfo.CurrentCulture,MvcResources.CshtmlView_ViewCouldNotBeCreated,ViewPath));}RenderView(viewContext, writer, instance);}protected abstract void RenderView(ViewContext viewContext, TextWriter writer, object instance);

 

  5.WebFormView类来继承并重写了RenderView方法,最终完成ViewData赋值给ViewPage类的ViewData字典属性,最后调用pr方法走完请求管道,页面生命周期最终完成MVC的数据的呈现     

//重写父类的抽象方法     protected override void RenderView(ViewContext viewContext, TextWriter writer, object instance) 
      {ViewPage viewPage = instance as ViewPage;if (viewPage != null) {//
                RenderViewPage(viewContext, viewPage);return;}ViewUserControl viewUserControl = instance as ViewUserControl;if (viewUserControl != null) {RenderViewUserControl(viewContext, viewUserControl);return;}throw new InvalidOperationException(String.Format(CultureInfo.CurrentCulture,MvcResources.WebFormViewEngine_WrongViewBase,ViewPath));}private void RenderViewPage(ViewContext context, ViewPage page){if (!String.IsNullOrEmpty(MasterPath)) {page.MasterLocation = MasterPath;}page.ViewData = context.ViewData;//调用ViewPage的RenderView方法,然后调用pr方法走完请求管道,页面生命周期最终完成MVC的数据的呈现
            page.RenderView(context);}