傻瓜教你看清MVC內部執行流程之ViewData數據傳輸,輕松學MVC--①目了然篇(待續)

1.首先在執行到Controller里面的action(方法)時,執行到最后會調用一個View()-->此方法是Controller的一個方法

源代碼:

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

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?2.然后繼續調用自己的View(參數1,參數2,參數3)帶三個參數的view()???

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 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};}

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?3.在上步View(string viewName, string masterName, object model)執行完畢將數據封裝到ViewResult(ActionResult的子類)中以后MVC會自己調用ViewResult的父類ViewResultBase的ExecuteResult(),方法里面會封裝好viewContext對象,并調用IView接口的Render()方法

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      public override void ExecuteResult(ControllerContext context){if (context == null) {throw new ArgumentNullException("context");}//其中會判斷View()是否有action名,沒有則會默認將"路由里面"的action賦值給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;//封裝數據到viewContext上下文中
ViewContext viewContext = new ViewContext(context, View, ViewData, TempData, writer);View.Render(viewContext, writer);//調用IView接口的Render()方法if (result != null) {result.ViewEngine.ReleaseView(context, View);}}

?未完待續...

?4.而IView接口是由BuildManagerCompiledView類實現的,此類乃是一個抽象類,最終是有WebFormView類來繼承并重寫了RenderView方法,最終完成ViewData賦值給ViewPage類的ViewData字典屬性,最后完成輸出顯示

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      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);

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? 5.WebFormView類來繼承并重寫了RenderView方法,最終完成ViewData賦值給ViewPage類的ViewData字典屬性,最后調用pr方法走完請求管道,頁面生命周期最終完成MVC的數據的呈現? ? ?

//重寫父類的抽象方法     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;//調用ViewPage的RenderView方法,然后調用pr方法走完請求管道,頁面生命周期最終完成MVC的數據的呈現
            page.RenderView(context);}

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