本篇内容介绍了“怎么给ASP.NET MVC及WebApi添加路由优先级”的有关知识，在实际案例的操作过程中，不少人都会遇到这样的困境，接下来就让小编带领大家学习一下如何处理这些情况吧！希望大家仔细阅读，能够学有所成！
一、为什么需要路由优先级
大家都知道我们在Asp.Net MVC项目或WebApi项目中注册路由是没有优先级的，当项目比较大、或有多个区域、或多个Web项目、或采用插件式框架开发时，我们的路由注册很可能 不是写在一个文件中的，而是分散在很多不同项目的文件中，这样一来，路由的优先级的问题就突显出来了。
比如： App_Start/RouteConfig.cs中
routes.MapRoute( name: "Default", url: "{controller}/{action}/{id}", defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional } ); Areas/Admin/AdminAreaRegistration.cs中 context.MapRoute( name: "Login", url: "login", defaults: new { area = "Admin", controller = "Account", action = "Login", id = UrlParameter.Optional }, namespaces: new string[] { "Wenku.Admin.Controllers" } );假如是先注册上面那个通用的default路由，再注册这个login的路由，那么无论怎么样，都会先匹配***个满足条件的路由，也就是第两个路由注册是无效的。
造成这个问题的原因就是这两个路由注册的顺序问题，而Asp.Net MVC及WebApi中注册路由都没有优先级这个概念，所以今天我们就是要自己实现这个想法，在注册路由时加入一个优先级的概念。
二、解决思路
先分析路由注册的入口，比如我们新建一个mvc4.0的项目
public class MvcApplication : System.Web.HttpApplication { protected void Application_Start() { AreaRegistration.RegisterAllAreas(); WebApiConfig.Register(GlobalConfiguration.Configuration); FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters); RouteConfig.RegisterRoutes(RouteTable.Routes); } }Mvc路由的注册入口有两个：
a. AreaRegistration.RegisterAllAreas(); 注册区域路由
b. RouteConfig.RegisterRoutes(RouteTable.Routes); 注册项目路由
WebApi路由注册入口有一个：
WebApiConfig.Register(GlobalConfiguration.Configuration); 注册WebApi路由
2、注册路由的处理类分析
AreaRegistrationContext
RouteCollection
HttpRouteCollection
注册路由时主要是由这三个类来注册处理路由的。
3、路由优先级方案
a、更改路由的注册入口
b、自定义一个路由的结构类RoutePriority及HttpRoutePriority，这两个类下面都有Priority这个属性
c、自定一个RegistrationContext来注册路由，注册的对象为上述自定义路由。
d、所有的路由注册完成之后再按优先顺序添加到RouteCollection及HttpRouteCollection中实际生效。
三、具体实现
1、路由定义
public class RoutePriority : Route { public string Name { get; set; } public int Priority { get; set; } public RoutePriority(string url, IRouteHandler routeHandler) : base(url,routeHandler) { } } public class HttpRoutePriority { public string Name { get; set; } public int Priority { get; set; } public string RouteTemplate{get;set;} public object Defaults{get;set;} public object Constraints{get;set;} public HttpMessageHandler Handler{get;set;} }2、定义路由注册的接口
public interface IRouteRegister { void Register(RegistrationContext context); }3、定义路由注册上下文类
public class RegistrationContext { #region mvc public List<RoutePriority> Routes = new List<RoutePriority>(); public RoutePriority MapRoute(string name, string url,int priority=0) { return MapRoute(name, url, (object)null , priority); } public RoutePriority MapRoute(string name, string url, object defaults, int priority = 0) { return MapRoute(name, url, defaults, (object)null , priority); } public RoutePriority MapRoute(string name, string url, object defaults, object constraints, int priority = 0) { return MapRoute(name, url, defaults, constraints, null , priority); } public RoutePriority MapRoute(string name, string url, string[] namespaces, int priority = 0) { return MapRoute(name, url, (object)null , namespaces, priority); } public RoutePriority MapRoute(string name, string url, object defaults, string[] namespaces,int priority=0) { return MapRoute(name, url, defaults, null , namespaces, priority); } public RoutePriority MapRoute(string name, string url, object defaults, object constraints, string[] namespaces, int priority = 0) { var route = MapPriorityRoute(name, url, defaults, constraints, namespaces, priority); var areaName = GetAreaName(defaults); route.DataTokens["area"] = areaName; // disabling the namespace lookup fallback mechanism keeps this areas from accidentally picking up // controllers belonging to other areas bool useNamespaceFallback = (namespaces == null || namespaces.Length == 0); route.DataTokens["UseNamespaceFallback"] = useNamespaceFallback; return route; } private static string GetAreaName(object defaults) { if (defaults != null) { var property = defaults.GetType().GetProperty("area"); if (property != null) return (string)property.GetValue(defaults, null); } return null; } private RoutePriority MapPriorityRoute(string name, string url, object defaults, object constraints, string[] namespaces,int priority) { if (url == null) { throw new ArgumentNullException("url"); } var route = new RoutePriority(url, new MvcRouteHandler()) { Name = name, Priority = priority, Defaults = CreateRouteValueDictionary(defaults), Constraints = CreateRouteValueDictionary(constraints), DataTokens = new RouteValueDictionary() }; if ((namespaces != null) && (namespaces.Length > 0)) { route.DataTokens["Namespaces"] = namespaces; } Routes.Add(route); return route; } private static RouteValueDictionary CreateRouteValueDictionary(object values) { var dictionary = values as IDictionary<string, object>; if (dictionary != null) { return new RouteValueDictionary(dictionary); } return new RouteValueDictionary(values); } #endregion #region http public List<HttpRoutePriority> HttpRoutes = new List<HttpRoutePriority>(); public HttpRoutePriority MapHttpRoute(string name, string routeTemplate, int priority = 0) { return MapHttpRoute(name, routeTemplate, defaults: null, constraints: null, handler: null, priority: priority); } public HttpRoutePriority MapHttpRoute(string name, string routeTemplate, object defaults, int priority = 0) { return MapHttpRoute(name, routeTemplate, defaults, constraints: null, handler: null, priority: priority); } public HttpRoutePriority MapHttpRoute(string name, string routeTemplate, object defaults, object constraints, int priority = 0) { return MapHttpRoute(name, routeTemplate, defaults, constraints, handler: null, priority: priority); } public HttpRoutePriority MapHttpRoute(string name, string routeTemplate, object defaults, object constraints, HttpMessageHandler handler, int priority = 0) { var httpRoute = new HttpRoutePriority(); httpRoute.Name = name; httpRoute.RouteTemplate = routeTemplate; httpRoute.Defaults = defaults; httpRoute.Constraints = constraints; httpRoute.Handler = handler; httpRoute.Priority = priority; HttpRoutes.Add(httpRoute); return httpRoute; } #endregion }4、把路由注册处理方法添加到Configuration类中
public static Configuration RegisterRoutePriority(this Configuration config) { var typesSoFar = new List<Type>(); var assemblies = GetReferencedAssemblies(); foreach (Assembly assembly in assemblies) { var types = assembly.GetTypes().Where(t => typeof(IRouteRegister).IsAssignableFrom(t) && !t.IsAbstract && !t.IsInterface); typesSoFar.AddRange(types); } var context = new RegistrationContext(); foreach (var type in typesSoFar) { var obj = (IRouteRegister)Activator.CreateInstance(type); obj.Register(context); } foreach (var route in context.HttpRoutes.OrderByDescending(x => x.Priority)) GlobalConfiguration.Configuration.Routes.MapHttpRoute(route.Name, route.RouteTemplate, route.Defaults, route.Constraints, route.Handler); foreach (var route in context.Routes.OrderByDescending(x => x.Priority)) RouteTable.Routes.Add(route.Name, route); return config; } private static IEnumerable<Assembly> GetReferencedAssemblies() { var assemblies = BuildManager.GetReferencedAssemblies(); foreach (Assembly assembly in assemblies) yield return assembly; }这样一来就大功告成，使用时只需要在Global.asax.cs文件中修改原注册入口为
public class MvcApplication : System.Web.HttpApplication { protected void Application_Start() { WebApiConfig.Register(GlobalConfiguration.Configuration); FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters); RouteConfig.RegisterRoutes(RouteTable.Routes); Configuration.Instance() .RegisterComponents() .RegisterRoutePriority(); //注册自定义路由 } }在每个项目中使用只需要要继承自定义路由注册接口IRouteRegister，例如：
public class Registration : IRouteRegister { public void Register(RegistrationContext context) { //注册后端管理登录路由 context.MapRoute( name: "Admin_Login", url: "Admin/login", defaults: new { area = "Admin", controller = "Account", action = "Login", id = UrlParameter.Optional }, namespaces: new string[] { "Wenku.Admin.Controllers" }, priority: 11 ); //注册后端管理页面默认路由 context.MapRoute( name: "Admin_default", url: "Admin/{controller}/{action}/{id}", defaults: new { area = "Admin", controller = "Home", action = "Index", id = UrlParameter.Optional }, namespaces: new string[] { "Wenku.Admin.Controllers" }, priority: 10 ); //注册手机访问WebApi路由 context.MapHttpRoute( name: "Mobile_Api", routeTemplate: "api/mobile/{controller}/{action}/{id}", defaults: new { area = "mobile", action = RouteParameter.Optional, id = RouteParameter.Optional, namespaceName = new string[] { "Wenku.Mobile.Http" } }, constraints: new { action = new StartWithConstraint() }, priority: 0 ); } }“怎么给ASP.NET MVC及WebApi添加路由优先级”的内容就介绍到这里了，感谢大家的阅读。如果想了解更多行业相关的知识可以关注编程网网站，小编将为大家输出更多高质量的实用文章！
