[聚合文章] Asp.net mvc 中View 的呈现(二)

//---------------------------------属性部分-------------------------------------//当前 View 所会用的强类型 modelpublic object Model{get{..}}//Controller 向 View传值使用的 TempData 集合public TempDataDictionary TempData{get{..} set{..}}// 当前ViewResult 所对应的View public IView View { get; set; }//Controller 向 View传值使用的 ViewBag 集合public dynamic ViewBag{     get       {           if (_dynamicViewData == null)            {               _dynamicViewData = new DynamicViewDataDictionary(()=>ViewData);            }                return _dynamicViewData;       }}//Controller 向 View传值使用的 ViewData 集合public ViewDataDictionary ViewData{get{..}set{..}}//用于解析视图的视图引擎的集合public ViewEngineCollection ViewEngineCollection{get{..}set{..}}//当前ViewResult 对应的 View的名称public string ViewName{get{..}set{..}}//---------------------------------方法部分-----------------------------------//根据 ControllerContext 查找对应的 IViewprotected abstract ViewEngineResult FindView(ControllerContext context);public override void ExecuteResult(ControllerContext context);

public interface IView{    void Render(ViewCotext viewContext,TextWritter textWritter);}

public class ViewResult : ViewResultBase{//---------------------------属性部分-----------------------------------------//当前 View 使用的模板页的名称public string MasterName{get{..}set{..}}//---------------------------方法部分-----------------------------------------protected override ViewEngineResult FindView(ControllerContext context){  //获取对应的 View 信息  ViewEngineResult result = ViewEngineCollection.FindView(context, ViewName, MasterName);  if (result.View != null)   {       return result;//查找成功   }   //查找失败，生成异常信息，其中包含查找过程中搜索的位置信息   StringBuilder locationsText = new StringBuilder();   foreach (string location in result.SearchedLocations)   {      locationsText.AppendLine();      locationsText.Append(location);   }   throw new InvalidOperationException(String.Format(CultureInfo.CurrentCulture,                                                   MvcResources.Common_ViewNotFound, ViewName, locationsText));        }}

public interface IViewEngine    {        ViewEngineResult FindPartialView(ControllerContext controllerContext, string partialViewName, bool useCache);                ViewEngineResult FindView(ControllerContext controllerContext, string viewName, string masterName, bool useCache);                void ReleaseView(ControllerContext controllerContext, IView view);    }

public class ViewEngineResult{        public ViewEngineResult(IEnumerable<string> searchedLocations);        public ViewEngineResult(IView view, IViewEngine viewEngine);                //定位视图时的查找路径        public IEnumerable<string> SearchedLocations { get; private set; }                //当前的 View        public IView View { get; private set; }                //查找时使用的视图引擎        public IViewEngine ViewEngine { get; private set; }}

public abstract class VirtualPathProviderViewEngine : IViewEngine{//----------------------------属性部分-----------------------------------------------//区域模板页存储位置格式模板, 型如，~/Areas/{2}/Views/{1}/{0}.cshtml等//其中的占位符最终会被替换为Area名称(如果有),Controller名称、Action名称public string[] AreaMasterLocationFormats { get; set; }//区域部分视图存储位置格式模板public string[] AreaPartialViewLocationFormats { get; set; }//区域视图存储位置格式模板public string[] AreaViewLocationFormats { get; set; }//模板页存储位置格式模板public string[] MasterLocationFormats { get; set; }//视图或模板页文件后缀，如cshtml，vbhtml等public string[] FileExtensions { get; set; }//部分视图存储位置格式模板public string[] PartialViewLocationFormats { get; set; }//视图存储位置格式模板，形如：~/Views/{1}/{0}.cshtml等public string ViewLocationFormats{get;set;}//----------------------------方法部分-----------------------------------------------//根据部分视图路径创建 IView实例protected abstract IView CreatePartialView(ControllerContext controllerContext, string partialPath);//根据视图文件创建 IView 实例protected abstract IView CreateView(ControllerContext controllerContext, string viewPath, string masterPath);//判断是否存在指定位置的文件protected virtual bool FileExists(ControllerContext controllerContext, string virtualPath);//IViewEngine 接口方法public virtual ViewEngineResult FindPartialView(ControllerContext controllerContext, string partialViewName, bool useCache){}public virtual ViewEngineResult FindView(ControllerContext controllerContext, string viewName, string masterName, bool useCache){}public virtual void ReleaseView(ControllerContext controllerContext, IView view){}}

public virtual ViewEngineResult FindView(ControllerContext controllerContext, string viewName, string masterName, bool useCache){ if (controllerContext == null){ //抛出参数异常 ...         }if (String.IsNullOrEmpty(viewName)){//抛出参数异常...string[] viewLocationsSearched;string[] masterLocationsSearched;//获取当前的控制器的名称string controllerName = controllerContext.RouteData.GetRequiredString("controller");//获取视图文件的存储路径string viewPath = GetPath(controllerContext, ViewLocationFormats, AreaViewLocationFormats, "ViewLocationFormats", viewName, controllerName, CacheKeyPrefixView, useCache, out viewLocationsSearched);//获取模板文件的存储位置string masterPath = GetPath(controllerContext, MasterLocationFormats, AreaMasterLocationFormats, "MasterLocationFormats", masterName, controllerName, CacheKeyPrefixMaster, useCache, out masterLocationsSearched);//查找失败，将搜索路径写入的返回结果中if (String.IsNullOrEmpty(viewPath) || (String.IsNullOrEmpty(masterPath) && !String.IsNullOrEmpty(masterName))){ return new ViewEngineResult(viewLocationsSearched.Union(masterLocationsSearched));}return new ViewEngineResult(CreateView(controllerContext, viewPath, masterPath), this);}

public abstract class BuildManagerViewEngine : VirtualPathProviderViewEngine{//--------------------------------构造函数------------------------------------protected BuildManagerViewEngine();protected BuildManagerViewEngine(IViewPageActivator viewPageActivator);internal BuildManagerViewEngine(IViewPageActivator viewPageActivator, IResolver<IViewPageActivator> activatorResolver,IDependencyResolver dependencyResolver, /*IOC 容器*/VirtualPathProvider pathProvider/*封装一组可以让Web应用从虚拟文件系统中检索资源的方法*/);//-----------------------------属性部分---------------------------------------//提供一组方法用于帮助 Asp.net 的编译工作管理，例如获取当前应用引用的程序集信息、根据虚拟路径获取//对应文件编译产生的类型等，详情可以查看 BuildManager 类internal IBuildManager BuildManager{get{..}set{..}}protected IViewPageActivator ViewPageActivator{get{..}}//---------------------------方法部分----------------------------------------//判断是否存在指定路径的文件，这里用于查找定位视图文件编译后产生的 .cs 文件protected override bool FileExists(ControllerContext controllerContext, string virtualPath);}

 public interface IViewPageActivator {        object Create(ControllerContext controllerContext, Type type);  }

public class RazorViewEngine{//定义启动页文件的名称internal static readonly string ViewStartFileName = "_ViewStart";public RazorViewEngine(IViewPageActivator viewPageActivator)            : base(viewPageActivator){    //区域中的视图的位置信息模板    AreaViewLocationFormats = new[]    {          "~/Areas/{2}/Views/{1}/{0}.cshtml",          "~/Areas/{2}/Views/{1}/{0}.vbhtml",          "~/Areas/{2}/Views/Shared/{0}.cshtml",          "~/Areas/{2}/Views/Shared/{0}.vbhtml"     };    //区域中视图模板的位置信息模板    AreaMasterLocationFormats = new[]    {         "~/Areas/{2}/Views/{1}/{0}.cshtml",         "~/Areas/{2}/Views/{1}/{0}.vbhtml",         "~/Areas/{2}/Views/Shared/{0}.cshtml",         "~/Areas/{2}/Views/Shared/{0}.vbhtml"    };   //区域中 分部视图的位置信息模板    AreaPartialViewLocationFormats = new[]    {          "~/Areas/{2}/Views/{1}/{0}.cshtml",          "~/Areas/{2}/Views/{1}/{0}.vbhtml",          "~/Areas/{2}/Views/Shared/{0}.cshtml",          "~/Areas/{2}/Views/Shared/{0}.vbhtml"     };     //视图的位置信息模板     ViewLocationFormats = new[]    {           "~/Views/{1}/{0}.cshtml",           "~/Views/{1}/{0}.vbhtml",           "~/Views/Shared/{0}.cshtml",           "~/Views/Shared/{0}.vbhtml"      };    //视图模板页的位置信息模板    MasterLocationFormats = new[]    {        "~/Views/{1}/{0}.cshtml",        "~/Views/{1}/{0}.vbhtml",        "~/Views/Shared/{0}.cshtml",        "~/Views/Shared/{0}.vbhtml"    };    //分部视图页存储位置信息模板    PartialViewLocationFormats = new[]   {        "~/Views/{1}/{0}.cshtml",        "~/Views/{1}/{0}.vbhtml",        "~/Views/Shared/{0}.cshtml",        "~/Views/Shared/{0}.vbhtml"    };   //视图文件扩展名集合   FileExtensions = new[]   {        "cshtml",        "vbhtml",    };  }//重写基类的方法，返回 RazorView 类型的实例protected override IView CreatePartialView(ControllerContext controllerContext, string partialPath);//重写基类的方法，返回 RazorView 类型实例protected override IView CreateView(ControllerContext controllerContext, string viewPath, string masterPath);}

public interface IView{       //渲染视图    void Render(ViewContext viewContext, TextWriter writer);}

public abstract class BuildManagerCompiledView : IView{//-----------------------------------构造函数---------------------------------protected BuildManagerCompiledView(ControllerContext controllerContext, string viewPath)    : this(controllerContext, viewPath, null);protected BuildManagerCompiledView(ControllerContext controllerContext, string viewPath, IViewPageActivator viewPageActivator)            : this(controllerContext, viewPath, viewPageActivator, null)}internal BuildManagerCompiledView(ControllerContext controllerContext, string viewPath, IViewPageActivator viewPageActivator, IDependencyResolver dependencyResolver);//------------------------------- 属性部分 -----------------------------------internal IBuildManager BuildManager{get{..}set{..}}//View文件的虚拟路径public string ViewPath { get; protected set; }//------------------------------- 方法部分 ----------------------------------//接口方法public virtual void Render(ViewContext viewContext, TextWriter writer);//视图渲染protected abstract void RenderView(ViewContext viewContext, TextWriter writer, object instance);

 public class RazorView : BuildManagerCompiledView { //---------------------------------构造函数--------------------------------- public RazorView(ControllerContext controllerContext, string viewPath, string layoutPath, bool runViewStartPages, IEnumerable<string> viewStartFileExtensions);public RazorView(ControllerContext controllerContext, string viewPath, string layoutPath, bool runViewStartPages, IEnumerable<string> viewStartFileExtensions, IViewPageActivator viewPageActivator);//--------------------------------- 属性部分 ---------------------------------//布局文件的存放路径public string LayoutPath { get; private set; }//是否使用启动页(_ViewStart.cshtml/_ViewStart.vbhtml)public bool RunViewStartPages { get; private set; }//获取 StartPage 的委托internal StartPageLookupDelegate StartPageLookup { get; set; }//该类型用于根据一个虚拟路径创建一个类型实例internal IVirtualPathFactory VirtualPathFactory { get; set; }//通过该类型可以实现针对不同的设备展示同一视图的不同的展示效果，详情请看://http://www.c-sharpcorner.com/UploadFile/b696c4/display-mode-provider-in-mvc-5-application/internal DisplayModeProvider DisplayModeProvider { get; set; }//启动页的文件名扩展public IEnumerable<string> ViewStartFileExtensions { get; private set; } }

protected override void RenderView(ViewContext viewContext, TextWriter writer, object instance){     if (writer == null)     {          throw new ArgumentNullException("writer");     }     WebViewPage webViewPage = instance as WebViewPage;     //获取视图实例失败     if (webViewPage == null)     {           throw new InvalidOperationException(                String.Format(                CultureInfo.CurrentCulture,                MvcResources.CshtmlView_WrongViewBase,                ViewPath));     }// An overriden master layout might have been specified when the    ViewActionResult got returned.// We need to hold on to it so that we can set it on the inner page once it has executed.   //这里针对调用 Controller的 View 方法时指定了 layout 参数的情况   webViewPage.OverridenLayoutPath = LayoutPath;   webViewPage.VirtualPath = ViewPath;   webViewPage.ViewContext = viewContext;   webViewPage.ViewData = viewContext.ViewData;      //初始化 HtmlHelper、UrlHelper等对象   webViewPage.InitHelpers();   if (VirtualPathFactory != null)   {   //改属性默认为一个 VirtualPathFactoryManager 实例       webViewPage.VirtualPathFactory = VirtualPathFactory;    }   if (DisplayModeProvider != null)   {         webViewPage.DisplayModeProvider = DisplayModeProvider;   }   WebPageRenderingBase startPage = null;  //是否使用启动页  if (RunViewStartPages)   {        startPage = StartPageLookup(webViewPage, RazorViewEngine.ViewStartFileName, ViewStartFileExtensions);  }    //执行视图的渲染工作,包括视图主体层级的渲染、Section的渲染，子视图的渲染  //此方法可以看作是视图渲染的入口方法，内部进行上述的类型的视图渲染  webViewPage.ExecutePageHierarchy(new WebPageContext(context: viewContext.HttpContext, page: null, model: null), writer, startPage);        }    }

public abstract class WebPageExecutingBase{//-------------------------------属性部分 ------------------------------------//跨请求和会话进行信息共享public virtual HttpApplicationStateBase AppState{get{..}}//当前请求的上下文信息public virtual HttpContextBase Context { get; set; }//提供页面的渲染过程中的监测服务internal InstrumentationService InstrumentationService{get{..}set{..}}//当前视图文件的虚拟路径public virtual string VirtualPath { get; set; }//根据虚拟路径创建一个指定文件的类型public virtual IVirtualPathFactory VirtualPathFactory{get{..}set{..}}//------------------------- 方法部分 ------------------------------------------////根据当前视图的虚拟路径及参数信息生成 urlpublic virtual string Href(string path, params object[] pathParts);//核心的方法，所有的视图的渲染工作都是在该方法中进行的或者说是以此方法为开端展开的public abstract void Execute();//将 result 写入到响应的输出流中，其中的 HelperResult 实现了 IHtmlString接口public abstract void Write(HelperResult result);//将 value 写入到响应的输出流中public abstract void Write(object value);//将 value 写入到响应的输出流中，这里侧重输出的内容为字面值public abstract void WriteLiteral(object value);//下面的三个方法用于 html 页面代码的生成，在 上面的Write/WriteLiteral等方法的子类实现中内部调用//下面的三个方法public static void WriteTo(TextWriter writer, HelperResult content)     public static void WriteTo(TextWriter writer, object content)        public static void WriteLiteralTo(TextWriter writer, object content)//获取输出流protected internal virtual TextWriter GetOutputWriter()}

public abstract class WebPageRenderingBase : WebPageExecutingBase, ITemplateFile{//-------------------------------- 属性部分 ---------------------------------//缓存对象，其值来自 HttpContext 的同名属性public virtual Cache Cache{get{..}}//布局文件的虚拟路径public abstract string Layout { get; set; }//存储与当前页面相关信息的字典，如页面的标题 titlepublic abstract IDictionary<object, dynamic> PageData { get; }//针对当前请求的 HttpRequest,其值来自 HttpContext的同名属性public virtual HttpRequestBase Request{get{..}}//针对当前请求的响应的 HttpResponse,其值来自 HttpContext 的同名属性public virtual HttpResponseBase Response{get{..}}//辅助工具类，封装一些请求处理常用的方法，如路径转换、Url编/解码等，其值来自 HttpContext 的同名属性public virtual HttpServerUtilityBase Server{get{..}}//会话，其值来自 HttpContext 的同名属性public virtual HttpSessionStateBase Session//当前上下文的用户，来自HttpContext 的同名属性public virtual IPrincipal User{get{..}internal set{..}}//当前请求方法是否为 POSTpublic virtual bool IsPost{get{..}}//当前请求是否为 Ajax 请求(判断Http头部的 X-Requested-With 字段是否为 XmlHttpRequest)public virtual bool IsAjax{get{..}}//-------------------------------- 方法部分 ----------------------------------//主体视图渲染，其中会调用 Execute() 方法public abstract void ExecutePageHierarchy();//渲染页面，path 表示要渲染的(子)视图的虚拟路径，data 表示渲染过程中使用的参数public abstract HelperResult RenderPage(string path, params object[] data);}

public abstract class WebPageBase : WebPageRenderingBase{ //---------------------------- 属性部分 ------------------------------------- //记录当前已渲染的 Section的信息，存储值为 Section 的 name, 这里的已渲染是指已调用   RenderSection 方法 private readonly HashSet<string> _renderedSections;//记录当前 body 是否已渲染，即是否已调用 RenderBody 方法private bool _renderedBody = false;//一个临时的 TextWritter,用于进行当前页面主体部分的渲染，最终会被合并进 _currentWritterprivate StringWriter _tempWriter;//当前渲染当前整体的 TextWritter，其被赋值为 HttpContext.Response.Output//private StringWritter _currentWritter;//当前所使用的 TextWritter，其值为 OutputStack 的栈顶元素public TextWriter Output;//存储有 所有 TextWritter 的栈 public Stack<TextWriter> OutputStack//-------------------------- 方法部分 --------------------------------------//根据虚拟路径创建类型实例，用于创建启动页或布局页的实例(通过IVirtualPathFactory)public static WebPageBase CreateInstanceFromVirtualPath(string virtualPath){..}//定义 Section，第一个参数为 Section 的名称，第二个参数为一个无参返回类型为void 的委托，用于将Section 内容写入到一个 TextWritter，在该类内部定义有一个 Dictionary<string,SectionWritter> 的字典，该方法内部就是将其存入到该字典中public void DefineSection(string name, SectionWriter action){..}//判断是否已定义指定名称的 section public bool IsSectionDefined(string name){..}//进行页面主体部分的渲染，在布局页中必须包括该方法public HelperResult RenderBody()//进行布局页或子视图的渲染，内部调用下面的 RenderPageCore 方法public override HelperResult RenderPage(string path, params object[] data)private HelperResult RenderPageCore(string path, bool isLayoutPage, object[] data)//进行 Section 的渲染，内部调用其重载 RenderSection(name,required:true),第二个参数表示该 Section是否为必须的public HelperResult RenderSection(string name)public HelperResult RenderSection(string name, bool required)}

public abstract class WebViewPage : WebPageBase, IViewDataContainer, IViewStartPageChild{    public override HttpContextBase Context;        public HtmlHelper<object> Html{..}    public AjaxHelper<object> Ajax{..}    internal string OverridenLayoutPath{..}    public TempDataDictionary TempData{..}    public object Model{get;set}    public UrlHelper Url { get; set; }       public ViewContext ViewContext { get; set; }    public ViewDataDictionary ViewData{..}//----------------------- 方法部分-------------------------------------------......}