17+个ASP.NET MVC扩展点,含源码{转}
1、自定义一个HttpModule，并将其中的方法添加到HttpApplication相应的事件中！
即：创建一个实现了IHttpmodule接口的类，并将配置WebConfig。在自定义的HttpModule中，可以将一个方法注册到HttpApplication的任意一个事件中，在之后执行HttpApplication一些列事件时，按照事件的顺序（事件又按照添加方法先后的顺序）执行注册在事件中的方法！
namespace MvcStore.Models { public class ExcuteHttpRequestModule:IHttpModule { public void Init(HttpApplication context) { context.PostResolveRequestCache+=new EventHandler(this.context_ExecuteHttpRequst); } public void Dispose() { } public void context_ExecuteHttpRequst(object sender, EventArgs e) { HttpRequest httpRequest = HttpContext.Current.Request; Uri previousUri = httpRequest.UrlReferrer; } } }
<?xml version="1.0" encoding="utf-8"?> <!-- 有关如何配置 ASP.NET 应用程序的详细信息，请访问 http://go.microsoft.com/fwlink/?LinkId=152368 --> <configuration> <appSettings> <add key="webpages:Version" value="1.0.0.0"/> <add key="ClientValidationEnabled" value="true"/> <add key="UnobtrusiveJavaScriptEnabled" value="true"/> </appSettings> <system.web> <!--自定义HttpModule，仅添加一下此段代码即可--> <httpModules> <add name="ExecuteHttpRequestModule" type="MvcStore.Models.ExcuteHttpRequestModule"/> </httpModules> ......等 </configuration>
例：创建一个HttpModule（实现IHttpModule接口），并将一个方法注册到HttpApplication的BeginRequest（HttpAppliaction的第一个事件）事件中，即：由于该方法注册在HttpApplication第一个事件中，所有无论是合法还是非法的请求地址，该方法都会被执行。
利用HttpModule扩展知识，并通过NLog来完成写请求日志：源码下载
补充：在ASP.NET MVC中，css和js的请求是合并到一起发送给服务端的！
2、添加路由规则
//微软定义的MapRoute方法
routes.MapRoute( "Default", // 路由名称 "{controller}/{action}/{id}", // 带有参数的 URL new { controller = "Home", action = "Index", id = UrlParameter.Optional } // 参数默认值 );
3、自定义MapRoute方法
第一步中MapRoute方法其实就是RouteCollection的扩展方法，我们也可以定义一个。
namespace System.Web.Mvc { public static class RouteCollectionExtensions { public static Route MapRoute(this RouteCollection routes, string name, string url) { return routes.MapRoute(name, url, null, null); } public static Route MapRoute(this RouteCollection routes, string name, string url, object defaults) { return routes.MapRoute(name, url, defaults, null); } public static Route MapRoute(this RouteCollection routes, string name, string url, object defaults, object constraints) { return routes.MapRoute(name, url, defaults, constraints, null); } public static Route MapRoute(this RouteCollection routes, string name, string url, string[] namespaces) { return routes.MapRoute(name, url, null, null, namespaces); } public static Route MapRoute(this RouteCollection routes, string name, string url, object defaults, string[] namespaces) { return routes.MapRoute(name, url, defaults, null, namespaces); } public static Route MapRoute(this RouteCollection routes, string name, string url, object defaults, object constraints, string[] namespaces) { if (routes == null) { throw new ArgumentNullException("routes"); } if (url == null) { throw new ArgumentNullException("url"); } Route route = new Route(url, new MvcRouteHandler()) { Defaults = new RouteValueDictionary(defaults), Constraints = new RouteValueDictionary(constraints), DataTokens = new RouteValueDictionary() }; if (namespaces != null && namespaces.Length > 0) { route.DataTokens["Namespaces"] = namespaces; } routes.Add(name, route); return route; } } }
//自定义的MapRoute方法 namespace MvcExtension.Models { public static class MyRouteCollectionExtensions { /// <summary> /// 自定义MapRoute方法 /// </summary> /// <param name="routes"></param> /// <param name="routeHandler"></param> /// <param name="name"></param> /// <param name="url"></param> /// <param name="defaults"></param> /// <param name="constraints"></param> /// <param name="namespaces"></param> /// <returns></returns> public static Route MyMapRoute(this RouteCollection routes, IRouteHandler routeHandler, string name, string url, object defaults, object constraints, string[] namespaces) { if (routes == null) { throw new ArgumentNullException("routes"); } if (url == null) { throw new ArgumentNullException("url"); } if (routeHandler == null) { throw new ArgumentNullException("routeHandler"); } Route route = new Route(url, routeHandler) { Defaults = new RouteValueDictionary(defaults), Constraints = new RouteValueDictionary(constraints), DataTokens = new RouteValueDictionary() }; if (namespaces != null && namespaces.Length > 0) { route.DataTokens["Namespaces"] = namespaces; } routes.Add(name, route); return route; } /// <summary> /// 自定义MapRoute方法 /// </summary> /// <param name="routes"></param> /// <param name="name"></param> /// <param name="route"></param> /// <returns></returns> public static Route MyMapRoute(this RouteCollection routes, string name, Route route) { if (routes == null) { throw new ArgumentNullException("routes"); } if (route == null) { throw new ArgumentNullException("route"); } routes.Add(name, route); return route; } } }
注：在微软提供的MapRoute方法中可以看出，创建Route对象时，其构造函数的参数中有：new MvcRouteHandler。这个MvcRouteHandler用于之后创建HttpHandler对象，HttpHandler就是用来最后处理请求的！
4、自定义MvcRouteHandler
即：实现IRouteHandler接口，MVC默认使用MvcRouteHandler来创建HttpHandler对象，用来处理请求！
//微软定义的MvcRouteHandler namespace System.Web.Mvc { public class MvcRouteHandler : IRouteHandler { private IControllerFactory _controllerFactory; public MvcRouteHandler() { } public MvcRouteHandler(IControllerFactory controllerFactory) { this._controllerFactory = controllerFactory; } protected virtual IHttpHandler GetHttpHandler(RequestContext requestContext) { requestContext.HttpContext.SetSessionStateBehavior(this.GetSessionStateBehavior(requestContext)); return new MvcHandler(requestContext); } protected virtual SessionStateBehavior GetSessionStateBehavior(RequestContext requestContext) { string controllerName = (string)requestContext.RouteData.Values["controller"]; IControllerFactory controllerFactory = this._controllerFactory ?? ControllerBuilder.Current.GetControllerFactory(); return controllerFactory.GetControllerSessionBehavior(requestContext, controllerName); } IHttpHandler IRouteHandler.GetHttpHandler(RequestContext requestContext) { return this.GetHttpHandler(requestContext); } } }
定义：我们自定义MvcRouteHandler时只需实现IRouteHandler接口，具体实现参照微软定义的MvcRouteHandler类
public class MyRouteHandler:IRouteHandler { public MyRouteHandler() { } protected virtual IHttpHandler GetHttpHandler(RequestContext requestContext) { return new MvcHandler(requestContext); } IHttpHandler IRouteHandler.GetHttpHandler(RequestContext requestContext) { return this.GetHttpHandler(requestContext); } }
使用：结合2中创建的自定义的MapRoute方法，将自己的MvcRouteHandler对象添加到Route对象中！
第2、3、4步骤示例：源码下载
5、自定义MvcHandler
对于微软的类MvcHandler其实就是一个HttpHandler（实现IHttpHandler接口），在MVC整个处理机制中，MvcHandler接收到请求并激活Controller、执行Action、View的呈现 等。MvcHandler是执行MvcRouteHandler的GetHttpHandler方法得到的！
public class MyMvcHandler : IHttpHandler { public bool IsReusable { get { return false; } } public void ProcessRequest(HttpContext context) { HttpContext.Current.Response.Write("自定义的MvcHandler处理请求"); } }
在第2、3、4步骤的基础上，使用自定义MvcHandler处理请求：源码下载
6、自定义ControllerFactory
ControllerFactory用于Controller的激活，也就是创建Controller对象。对于MVC，这个ControllerFactiory是通过ControllerBuilder.Current.GetControllerFactory();得到，默认得到的ControllerFactory是DefaultControllerFactory对象！
public class MvcHandler : IHttpAsyncHandler, IHttpHandler, IRequiresSessionState { internal ControllerBuilder ControllerBuilder { get { if (this._controllerBuilder == null) { this._controllerBuilder = ControllerBuilder.Current; } return this._controllerBuilder; } set { this._controllerBuilder = value; } } protected virtual void ProcessRequest(HttpContext httpContext) { HttpContextBase httpContext2 = new HttpContextWrapper(httpContext); this.ProcessRequest(httpContext2); } protected internal virtual void ProcessRequest(HttpContextBase httpContext) { SecurityUtil.ProcessInApplicationTrust(delegate { IController controller; IControllerFactory controllerFactory; this.ProcessRequestInit(httpContext, out controller, out controllerFactory); try { controller.Execute(this.RequestContext); } finally { controllerFactory.ReleaseController(controller); } }); } private void ProcessRequestInit(HttpContextBase httpContext, out IController controller, out IControllerFactory factory) { if (ValidationUtility.IsValidationEnabled(HttpContext.Current) == true) { ValidationUtility.EnableDynamicValidation(HttpContext.Current); } this.AddVersionHeader(httpContext); this.RemoveOptionalRoutingParameters(); string requiredString = this.RequestContext.RouteData.GetRequiredString("controller"); //获取ControllerFactory factory = this.ControllerBuilder.GetControllerFactory(); controller = factory.CreateController(this.RequestContext, requiredString); if (controller == null) { throw new InvalidOperationException(string.Format(CultureInfo.CurrentCulture, MvcResources.ControllerBuilder_FactoryReturnedNull, new object[] { factory.GetType(), requiredString })); } } } MvcHandler
public class ControllerBuilder { private Func<IControllerFactory> _factoryThunk = () => null; //静态变量，自己创建本身对象 private static ControllerBuilder _instance = new ControllerBuilder(); private HashSet<string> _namespaces = new HashSet<string>(StringComparer.OrdinalIgnoreCase); private IResolver<IControllerFactory> _serviceResolver; //Current public static ControllerBuilder Current { get { return ControllerBuilder._instance; } } public HashSet<string> DefaultNamespaces { get { return this._namespaces; } } public ControllerBuilder() : this(null) { } internal ControllerBuilder(IResolver<IControllerFactory> serviceResolver) { IResolver<IControllerFactory> arg_6A_1 = serviceResolver; if (serviceResolver == null) { //默认情况下，_serviceResolver赋值为new DefaultControllerFactory arg_6A_1 = new SingleServiceResolver<IControllerFactory>(() => this._factoryThunk(), new DefaultControllerFactory { ControllerBuilder = this }, "ControllerBuilder.GetControllerFactory"); } this._serviceResolver = arg_6A_1; } public IControllerFactory GetControllerFactory() { //_serviceResolver.Current得到的是DefaultControllerFactory对象，在构造函数中赋值 return this._serviceResolver.Current; } public void SetControllerFactory(IControllerFactory controllerFactory) { if (controllerFactory == null) { throw new ArgumentNullException("controllerFactory"); } this._factoryThunk = (() => controllerFactory); } public void SetControllerFactory(Type controllerFactoryType) { if (controllerFactoryType == null) { throw new ArgumentNullException("controllerFactoryType"); } if (!typeof(IControllerFactory).IsAssignableFrom(controllerFactoryType)) { throw new ArgumentException(string.Format(CultureInfo.CurrentCulture, MvcResources.ControllerBuilder_MissingIControllerFactory, new object[] { controllerFactoryType }), "controllerFactoryType"); } this._factoryThunk = delegate { IControllerFactory result; try { result = (IControllerFactory)Activator.CreateInstance(controllerFactoryType); } catch (Exception innerException) { throw new InvalidOperationException(string.Format(CultureInfo.CurrentCulture, MvcResources.ControllerBuilder_ErrorCreatingControllerFactory, new object[] { controllerFactoryType }), innerException); } return result; }; } } ControllerBuilder
上述两个类，MvcHandler中通过GetControllerFactory获取的就是通过ControllerBuilder的SetControllerFactory方法设置ControllerFactory（没有设置时，默认是DefaultControllerFactory）。这就是我们创建自定义ControllerFactory的入口
public class MyControllerFactory:IControllerFactory { public IController CreateController(System.Web.Routing.RequestContext requestContext, string controllerName) { //根据controllerName和命名空间，通过反射创建Controller对象 return null; } public System.Web.SessionState.SessionStateBehavior GetControllerSessionBehavior(System.Web.Routing.RequestContext requestContext, string controllerName) { //获取控制器的会话行为。 return System.Web.SessionState.SessionStateBehavior.Default;//这里是随便列举的一个 } public void ReleaseController(IController controller) { //释放Controller } }
public class MvcApplication : System.Web.HttpApplication { public static void RegisterGlobalFilters(GlobalFilterCollection filters) { filters.Add(new HandleErrorAttribute()); } public static void RegisterRoutes(RouteCollection routes) { routes.IgnoreRoute("{resource}.axd/{*pathInfo}"); routes.MapRoute( "Default", // 路由名称 "{controller}/{action}/{id}", // 带有参数的 URL new {controller = "Home", action = "Index", id = UrlParameter.Optional} // 参数默认值 ); } protected void Application_Start() { AreaRegistration.RegisterAllAreas(); RegisterGlobalFilters(GlobalFilters.Filters); RegisterRoutes(RouteTable.Routes); //设置MyControllerFactory，让MyControllerFactory完成controller的激活 ControllerBuilder.Current.SetControllerFactory(new MyControllerFactory()); } }
上面就是简单的列举了执行流程，不再进行过多的介绍，因为在实际开发中，一般不会使用自定义一个ControllerFactory，因为其中包含的功能，我们自己来定义时可能考虑的不够全面，如果项目需求必须使用的话，要细看微软在DefaultControllerFactory中各种功能！！！既然不用自定义的ContollerFactory，那么就只能用DefaultControllerFactory了，DefaultControllerFactory中也有扩展点让我们利用，就是下面第7中介绍的！
7、自定义ControllerActivator
在6中我们讲到，DefaultControllerFactory用于创建Controller对象，而这个ControllerActivator实际上就是DefaultControllerFactory中负责创建Controller对象“组件”。默认情况下，使用的是微软提供的DefaultControllerActivator（DefaultControllerFactory的构造函数中设置）。
private class DefaultControllerActivator : IControllerActivator { private Func<IDependencyResolver> _resolverThunk; public DefaultControllerActivator() : this(null) { } public DefaultControllerActivator(IDependencyResolver resolver) { if (resolver == null) { this._resolverThunk = (() => DependencyResolver.Current); return; } this._resolverThunk = (() => resolver); } public IController Create(RequestContext requestContext, Type controllerType) { IController result; try { result = (IController)(this._resolverThunk().GetService(controllerType) ?? Activator.CreateInstance(controllerType)); } catch (Exception innerException) { throw new InvalidOperationException(string.Format(CultureInfo.CurrentCulture, MvcResources.DefaultControllerFactory_ErrorCreatingController, new object[] { controllerType }), innerException); } return result; } } 微软：DefaultControllerActivator
自定义：
定义：实现IControllerActivator接口
使用：通过DefaultControllerFactory的构造函数将自定义ControllerActivator “注入”。
在Global.asax中添加 ---> ControllerBuilder.Current.SetControllerFactory(new DefaultControllerFactory(new MyControllerActivator()));
public class MyControllerActivator:IControllerActivator { public IController Create(System.Web.Routing.RequestContext requestContext, Type controllerType) { return (IController)Activator.CreateInstance(controllerType); } }
protected void Application_Start() { AreaRegistration.RegisterAllAreas(); RegisterGlobalFilters(GlobalFilters.Filters); RegisterRoutes(RouteTable.Routes); ControllerBuilder.Current.SetControllerFactory(new DefaultControllerFactory(new MyControllerActivator())); }
应用场景1：在Controller激活之前做一些操作
应用场景2：通过Controller的构造函数实现在创建Controller对象时“注入”值！因为默认情况下，激活Controller的时候是执行的其无参数构造函数！
应用场景2+依赖注入：源码下载
8、自定义ActionInvoker
ActionInvoker用于去执行被请求的Action方法，这过程中包含了 View的呈现 以及执行各种应用在Action上的特性（HttpMethod、Filter、DisplayName...等），由于功能忒多，所以不到不得已也不建议自己重写ActionInvoker。不过如果项目需要，可以继承微软默认使用的 ControllerActionInvoker，从而在已有功能的基础上添加自己的需要的功能！
自定义：
定义：实现IActionInvoker接口
使用：在Controller的构造函数中设置自己的ActionInvoker
public class MyActionInvoker:IActionInvoker { public bool InvokeAction(ControllerContext controllerContext, string actionName) { //根据action名称去找Action并执行，其中包括了 View的呈现 以及 应用在Action上的各种特性的执行 //return false; //执行失败 return true; //执行成功 } }
public class HomeController : Controller { //微软的ControllerActivator激活Controller时，执行的就是无参数的构造函数！ public HomeController() { base.ActionInvoker = new MyActionInvoker(); } public ActionResult Index() { return Content("ddd"); } }
仅第8步骤示例：源码下载
下面的9、10、11讲的是和特性相关的扩展，所以在介绍它们之前先来复习下MVC中使用的特性种类和处理流程：
种类：
ActionNameSelectorAttribute
ActionNameAttribute
ActionMethodSelectorAttribute
AcceptVerbsAttribute
HttpDeleteAttribute
HttpGetAttribute
HttpPostAttribute
HttpPutAttribute
NonActionAttribute
HttpHeadAttribute
HttpOptionsAttribute
HttpPatchAttribute //灰色字体的是MVC4中新增的！
FilterAttribute、IActionFilter或IAuthorizationFilter或IExceptionFilter或IResultFilter
自定义类去实现相应接口
处理流程：Contrller激活之后，要从Controller对象的方法中查找当前请求的Action，那么其流程为 ----> 先获取所有应用了ActionName特性并且ActionName特性设置的name=当前请求的Action名称（将符合条件的添加的List<MethodInfo>中），之后去获取所有没有应用ActionName特性的方法并且方法名=当前请求的Action名称，（再将符合条件的添加到之前创建的List<MethodInfo>尾部）；再之后对符合名称条件的Action方法集合处理，判断应用在Action方法上的NonAction、AcceptVerbs、HttpGet等6个特性（MVC4有9个特性）是否和当前请求一致；再再之后执行第三种过滤器，需要自己定义且实现接口，并应用在Action上，他们的执行顺序为：【IAuthorizationFilter】--->【IActionFilter】--->【Action方法内部代码】--->【IResultFilter】，如果上述4个过程中有异常抛出，则执行【IExceptionFilter】。个更多处理流程的介绍请猛击这里！
9、继承自ActionNameSelectorAttribute 的特性：ActionNameAttribute
用于对Controller类中Action方法的重命名！当请求指定的 Controller/Action时，将用重命名后的名称去和请求的Action名称匹配。
[AttributeUsage(AttributeTargets.Method, AllowMultiple = false, Inherited = true)] public sealed class ActionNameAttribute : ActionNameSelectorAttribute { public string Name { get; private set; } public ActionNameAttribute(string name) { if (string.IsNullOrEmpty(name)) { throw new ArgumentException(MvcResources.Common_NullOrEmpty, "name"); } this.Name = name; } public override bool IsValidName(ControllerContext controllerContext, string actionName, MethodInfo methodInfo) { return string.Equals(actionName, this.Name, StringComparison.OrdinalIgnoreCase); } } 微软定义的ActionNameAttribute
public class HomeController : Controller { [ActionName("OtherName")] public ActionResult Index() { return Content("ddd"); } }
如上设置ActionName后，当请求Home/Index就提示找不到无法找到资源，当请求Home/OtherName时，就会去执行这个Index方法！
10、继承自ActionMethodSelectorAttribute的特性：AcceptVerbsAttribute...等
该类特性中仅NonAction用于指示该方法不作为Action来使用，而其他的5个则都是用于判断Http请求的方式！
HttpGet 只有客户端发送的是Get请求才能执行该Action
HttpPost 只有客户端发送的是Post请求才能执行该Action ...Post请求
HttpDelete 只有客户端发送的是Delete请求才能执行该Action
HttpPut 只有客户端发送的是Put请求才能执行该Action
AcceptVerbs 参数是一个枚举（Get、Post等），其功能和以上四个相同
注：由于以上的特性类都应用了： [AttributeUsage(AttributeTargets.Method, AllowMultiple = false, Inherited = true)]，所以这些特性只能应用在Action方法上并且每个只能使用一个。
使用：仅列出HttpPost，其他使用方法相同，不再列举。
public class HomeController : Controller { [HttpPost] public ActionResult Index() { return Content("ddd"); } }
如上所示，只有客户端发送的是Post请求时，才能执行该Action。
11、FilterAttribute、IActionFilter或IAuthorizationFilter或IExceptionFilter或IResultFilter
该类过滤器执行的顺序为：【IAuthorizationFilter】--->【IActionFilter】--->【Action方法内部代码】--->【IResultFilter】，如果上述4个过程中有异常抛出，则执行【IExceptionFilter】。
由于FilterAttribute类应用了 [AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, Inherited = true, AllowMultiple = false)]，所以该类特性可以应用在 类 或 方法 上且默认也只能使用一次，如果想要使用多个同样的特性，可以在自定义的特性上添加： [AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, Inherited = true, AllowMultiple = true)]即可。
该类过滤器有 4 种添加方式：以特性应用在Action方法上、以特性应用在Controller类上、Global.asax文件中RegisterGlobalFilters方法中添加、在Controller中重写各个过滤器方法（因为Controller类都实现各个接口），区别是这4种方式的作用域不同！
11-1、IAuthorizationFilter
public class MyAuthroizeFilter : FilterAttribute, IAuthorizationFilter { public void OnAuthorization(AuthorizationContext filterContext) { //如果此处为filterContext.Result赋一个ActionResult对象，则MVC不会再继续执行下面的过滤器和Action放，而是直接根据这个ActionResult对象进行View的呈现。 //如果filterContext.Result为null，则MVC继续执行之后的各个过滤器和Action方法！ } }
using System; namespace System.Web.Mvc { /// <summary>Represents an attribute that is used to indicate that an action method should be called only as a child action.</summary> [AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = false, Inherited = true)] public sealed class ChildActionOnlyAttribute : FilterAttribute, IAuthorizationFilter { /// <summary>Called when authorization is required.</summary> /// <param name="filterContext">An object that encapsulates the information that is required in order to authorize access to the child action.</param> public void OnAuthorization(AuthorizationContext filterContext) { if (filterContext == null) { throw new ArgumentNullException("filterContext"); } if (!filterContext.IsChildAction) { throw Error.ChildActionOnlyAttribute_MustBeInChildRequest(filterContext.ActionDescriptor); } } } } ChildActionOnlyAttribute
using System; using System.Collections.Generic; using System.Linq; using System.Security.Principal; using System.Web.Mvc.Resources; namespace System.Web.Mvc { /// <summary>Represents an attribute that is used to restrict access by callers to an action method.</summary> [AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, Inherited = true, AllowMultiple = true)] public class AuthorizeAttribute : FilterAttribute, IAuthorizationFilter { private readonly object _typeId = new object(); private string _roles; private string[] _rolesSplit = new string[0]; private string _users; private string[] _usersSplit = new string[0]; /// <summary>Gets or sets the user roles.</summary> /// <returns>The user roles.</returns> public string Roles { get { return this._roles ?? string.Empty; } set { this._roles = value; this._rolesSplit = AuthorizeAttribute.SplitString(value); } } /// <summary>Gets the unique identifier for this attribute.</summary> /// <returns>The unique identifier for this attribute.</returns> public override object TypeId { get { return this._typeId; } } /// <summary>Gets or sets the authorized users.</summary> /// <returns>The authorized users.</returns> public string Users { get { return this._users ?? string.Empty; } set { this._users = value; this._usersSplit = AuthorizeAttribute.SplitString(value); } } /// <summary>When overridden, provides an entry point for custom authorization checks.</summary> /// <returns>true if the user is authorized; otherwise, false.</returns> /// <param name="httpContext">The HTTP context, which encapsulates all HTTP-specific information about an individual HTTP request.</param> /// <exception cref="T:System.ArgumentNullException">The <paramref name="httpContext" /> parameter is null.</exception> protected virtual bool AuthorizeCore(HttpContextBase httpContext) { if (httpContext == null) { throw new ArgumentNullException("httpContext"); } IPrincipal user = httpContext.User; return user.Identity.IsAuthenticated && (this._usersSplit.Length <= 0 || this._usersSplit.Contains(user.Identity.Name, StringComparer.OrdinalIgnoreCase)) && (this._rolesSplit.Length <= 0 || this._rolesSplit.Any(new Func<string, bool>(user.IsInRole))); } private void CacheValidateHandler(HttpContext context, object data, ref HttpValidationStatus validationStatus) { validationStatus = this.OnCacheAuthorization(new HttpContextWrapper(context)); } /// <summary>Called when a process requests authorization.</summary> /// <param name="filterContext">The filter context, which encapsulates information for using <see cref="T:System.Web.Mvc.AuthorizeAttribute" />.</param> /// <exception cref="T:System.ArgumentNullException">The <paramref name="filterContext" /> parameter is null.</exception> public virtual void OnAuthorization(AuthorizationContext filterContext) { if (filterContext == null) { throw new ArgumentNullException("filterContext"); } if (OutputCacheAttribute.IsChildActionCacheActive(filterContext)) { throw new InvalidOperationException(MvcResources.AuthorizeAttribute_CannotUseWithinChildActionCache); } if (this.AuthorizeCore(filterContext.HttpContext)) { HttpCachePolicyBase cache = filterContext.HttpContext.Response.Cache; cache.SetProxyMaxAge(new TimeSpan(0L)); cache.AddValidationCallback(new HttpCacheValidateHandler(this.CacheValidateHandler), null); return; } this.HandleUnauthorizedRequest(filterContext); } /// <summary>Processes HTTP requests that fail authorization.</summary> /// <param name="filterContext">Encapsulates the information for using <see cref="T:System.Web.Mvc.AuthorizeAttribute" />. The <paramref name="filterContext" /> object contains the controller, HTTP context, request context, action result, and route data.</param> protected virtual void HandleUnauthorizedRequest(AuthorizationContext filterContext) { filterContext.Result = new HttpUnauthorizedResult(); } /// <summary>Called when the caching module requests authorization.</summary> /// <returns>A reference to the validation status.</returns> /// <param name="httpContext">The HTTP context, which encapsulates all HTTP-specific information about an individual HTTP request.</param> /// <exception cref="T:System.ArgumentNullException">The <paramref name="httpContext" /> parameter is null.</exception> protected virtual HttpValidationStatus OnCacheAuthorization(HttpContextBase httpContext) { if (httpContext == null) { throw new ArgumentNullException("httpContext"); } if (!this.AuthorizeCore(httpContext)) { return HttpValidationStatus.IgnoreThisRequest; } return HttpValidationStatus.Valid; } internal static string[] SplitString(string original) { if (string.IsNullOrEmpty(original)) { return new string[0]; } IEnumerable<string> source = from piece in original.Split(new char[] { ',' }) let trimmed = piece.Trim() where !string.IsNullOrEmpty(trimmed) select trimmed; return source.ToArray<string>(); } } } AuthorizeAttribute
==注意：如果在Controller上应用多个不同的IAuthorizationFilter过滤器，他们执行的顺序：由下向上。
11-2、IActionFilter--->Action方法内部代码--->IResultFilter
IActionFilter有两个方法OnActionExecuting（在执行操作方法之前调用）、OnActionExecuted（在执行操作方法后调用）。IResultFilter也有两个方法OnResultExecuting（在操作结果执行之前调用）、OnResultExecuted（在操作结果执行后调用），由于这里说的【在执行操作方法后调用】和【在操作结果执行之前调用】容易造成混淆，这里我们就来确定的说明一下其执行流程为：OnActionExecuting--->OnActionExecuted--->Action方法内的代码--->OnResultExecuting--->OnResultExecuted
public class MyActionFilter :FilterAttribute, IActionFilter { public void OnActionExecuted(ActionExecutedContext filterContext) { //如果此处为filterContext.Result赋一个ActionResult对象，则MVC不会再继续执行下面的过滤器，而是直接根据这个ActionResult对象进行View的呈现。 //如果filterContext.Result为null，则MVC按照 Action方法内返回的ActionResult进行View的呈现 } public void OnActionExecuting(ActionExecutingContext filterContext) { //如果此处为filterContext.Result赋一个ActionResult对象，则MVC不会再继续执行下面的过滤器和Action方法，而是直接根据这个ActionResult对象进行View的呈现。 //如果filterContext.Result为null，则MVC继续执行之后的各个过滤器和Action方法！ } } public class MyResultFilter : FilterAttribute,IResultFilter { public void OnResultExecuted(ResultExecutedContext filterContext) { //如果此处为filterContext.Result赋一个ActionResult对象，MVC会直接根据这个ActionResult对象进行View的呈现。 //如果filterContext.Result为null，则MVC按照 Action方法内返回的ActionResult进行View的呈现 } public void OnResultExecuting(ResultExecutingContext filterContext) { //如果此处为filterContext.Result赋一个ActionResult对象，MVC会直接根据这个ActionResult对象进行View的呈现。 //如果filterContext.Result为null，则MVC按照 Action方法内返回的ActionResult进行View的呈现 } }
11-3、IExceptionFilter
Action方法上应用该特性后，如果执行：IAuthorizationFilter过滤器、IActionFilter过滤器、Action方法内的代码、IResultFilter过滤器，抛出了异常，则会执行该方法!（只要出现有异常，则不会再继续往下执行后面的过滤器）
public class MyExceptionFilter : FilterAttribute, IExceptionFilter { public void OnException(ExceptionContext filterContext) { //如果filterContext.ExceptionHandled = false（默认）,则直接抛出异常。（filterContext.ExceptionHandled表示是否已经处理异常） //否则，为filterContext.Result赋一个ActionResult，使用这个ActionResult执行View的呈现！ } }
12、自定义ActionResult
自定义一个ActionResult，只需要继承抽象类ActionResult，并实现其抽象方法ExecuteResult即可！微软中已经定义很多ActionResult（EmptyResult、ContentResult、JsonResult、ViewResult等）。
public class MyActionResult : ActionResult { public override void ExecuteResult(ControllerContext context) { HttpContext.Current.Response.Write("自定义的ActionResult"); } }
使用时，只需要创建一个MyActionResult对象并让Action方法将其返回，或者在第11中任何一个过滤器中创建一个MyActionResult对象并赋值给filterContext.Result。下面是两个使用MyActionResult的例子：
public class HomeController : Controller { public ActionResult Index() { return new MyActionResult(); } }
public class HomeController : Controller { [MyAuthroizeFilter] public ActionResult Index() { return Content("123"); } } public class MyAuthroizeFilter : FilterAttribute, IAuthorizationFilter { public void OnAuthorization(AuthorizationContext filterContext) { filterContext.Result = new MyActionResult(); } }
定义一个生成验证码的VerifyCodeResult示例：源码下载
13、自定义HtmlHelper
在 .cshtml 文件中 使用的 @Html.TextBox(...)等，他们都是HtmlHelper类的扩展方法（定义在System.Web.Mvc.Html.InputExtensions中），更多关于@Html.xxx()方法的详细介绍请：猛击这里
public static class MyHtmlHelperExtensions { public static MvcHtmlString MyControl(this HtmlHelper html, string str) { return MvcHtmlString.Create("自定义Html标签"); } }
使用HtmlHelper扩展开发一个【分页功能】：源码下载
14、自定义ModelBinder
15、自定义ValueProvider
在学习 第14、15 扩展点之前，先来思考下！ 在我们定义的Action方法中，他们的参数值是如何得到的呢？
答：通过这第14、15个扩展点会让你对参数值的得到有个清楚的认识！在我的《白话学习MVC系列》的模型绑定一篇中已经做了详细的介绍！【猛击这里】
下面的第16、17扩展点是【View呈现】步骤中，寻找【视图页】过程中用到的，详细介绍：猛击这里
16、指定DefaultDisplayMode
模拟需求：对Phone端用户的某个Action请求，返回电脑版网页。
public ActionResult Index() { this.ControllerContext.DisplayMode = DisplayModeProvider.Instance.Modes[1]; DisplayModeProvider.Instance.RequireConsistentDisplayMode = true; return View(); }
根据上述设置，即使是Phone端的请求并且还存在Index.Mobile.cshtml文件，也会去执行Index.cshtml，即：实现Phone用户访问电脑版网页。
17、自定义DefaultDisplayMode
模拟需求：为Android 2.3用户设置特定的页面
先创建一个类似于Index.Android23.cshtml 的页面，然后在Global.asax中做如下设置即可：
public class MvcApplication : System.Web.HttpApplication { protected void Application_Start() { AreaRegistration.RegisterAllAreas(); WebApiConfig.Register(GlobalConfiguration.Configuration); FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters); RouteConfig.RegisterRoutes(RouteTable.Routes); BundleConfig.RegisterBundles(BundleTable.Bundles); AuthConfig.RegisterAuth(); DisplayModeProvider.Instance.Modes.Insert(0, new DefaultDisplayMode("Android23") { ContextCondition = (context => context.GetOverriddenUserAgent().IndexOf ("Android 2.3", StringComparison.OrdinalIgnoreCase) >= 0) }); } }