VS2013和VS2015中MVC 区域路由匹配顺序相反

创建测试工程

分别在vs2013和vs2015中创建mvc项目，并创建First、Second、Three三个Area，每个Area下面创建一个HomeController和Index视图。修改RouteConfig.cs中的路由注册方法，添加命名空间

       public static void RegisterRoutes(RouteCollection routes)
        {
            routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

            routes.MapRoute(
                name: "Default",
                url: "{controller}/{action}/{id}",
                defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional },
                namespaces: new[] { "RouteDebuggerMvc5Demo.Controllers" }
            );
        }

修改三个Area的路由注册方法，添加命名空间：

  public class FirstAreaRegistration : AreaRegistration
    {
        public override string AreaName
        {
            get
            {
                return "First";
            }
        }

        public override void RegisterArea(AreaRegistrationContext context)
        {
            context.MapRoute(
                "First_default",
                "First/{controller}/{action}/{id}",
                new { action = "Index", id = UrlParameter.Optional },
                namespaces: new[] { "RouteDebuggerMvc5Demo.Areas.First.Controllers" }
            );
        }
    }

使用nuget添加RouteDebugger引用,在Web.config中配置启用 <add key="RouteDebugger:Enabled" value="true" />，运行起来：

VS2013中升序

Matches Current Request	Url	Defaults	Constraints	DataTokens
False	First/{controller}/{action}/{id}	action = Index, id = UrlParameter.Optional	(empty)	Namespaces = RouteDebuggerMvc5Demo.Areas.First.Controllers, area = First, UseNamespaceFallback = False
False	Second/{controller}/{action}/{id}	action = Index, id = UrlParameter.Optional	(empty)	Namespaces = RouteDebuggerMvc5Demo.Areas.Second.Controllers, area = Second, UseNamespaceFallback = False
False	Three/{controller}/{action}/{id}	action = Index, id = UrlParameter.Optional	(empty)	Namespaces = RouteDebuggerMvc5Demo.Areas.Three.Controllers, area = Three, UseNamespaceFallback = False
False	{resource}.axd/{*pathInfo}	(null)	(empty)	(null)
True	{controller}/{action}/{id}	controller = Home, action = Index, id = UrlParameter.Optional	(empty)	Namespaces = RouteDebuggerMvc5Demo.Controllers
True	{*catchall}	(null)	(null)	(null)

VS2015中降序

All Routes

Matches Current Request	Url	Defaults	Constraints	DataTokens
False	Three/{controller}/{action}/{id}	action = Index, id = UrlParameter.Optional	(empty)	Namespaces = RouteDebuggerDemo.Areas.Three.Controllers, RouteDebuggerDemo, area = Three, UseNamespaceFallback = False
False	Second/{controller}/{action}/{id}	action = Index, id = UrlParameter.Optional	(empty)	Namespaces = RouteDebuggerDemo.Areas.Second.Controllers, RouteDebuggerDemo, area = Second, UseNamespaceFallback = False
False	First/{controller}/{action}/{id}	action = Index, id = UrlParameter.Optional	(empty)	Namespaces = RouteDebuggerDemo.Areas.First.Controllers, RouteDebuggerDemo, area = First, UseNamespaceFallback = False
False	{resource}.axd/{*pathInfo}	(null)	(empty)	(null)
True	{controller}/{action}/{id}	controller = Home, action = Index, id = UrlParameter.Optional	(empty)	Namespaces = RouteDebuggerDemo.Controllers, RouteDebuggerDemo
True	{*catchall}	(null)	(null)	(null)

如果在VS2013中的某个路由注册有问题，一直没有显现出来，升级到VS2015后出现了404就有可能是路由匹配顺序导致的。问题参考：Why did the order of Areas in RegisterAllAreas change with Visual Studio 2015?

手动修改路由顺序

默认在 *.csproj文件中的路由顺序是

<Compile Include="Areas\First\Controllers\HomeController.cs" />
<Compile Include="Areas\First\FirstAreaRegistration.cs" />
<Compile Include="Areas\Second\Controllers\HomeController.cs" />
<Compile Include="Areas\Second\SecondAreaRegistration.cs" />
<Compile Include="Areas\Three\Controllers\HomeController.cs" />
<Compile Include="Areas\Three\ThreeAreaRegistration.cs" />

修改成

<Compile Include="Areas\First\Controllers\HomeController.cs" />
<Compile Include="Areas\First\FirstAreaRegistration.cs" />
<Compile Include="Areas\Three\Controllers\HomeController.cs" />
<Compile Include="Areas\Three\ThreeAreaRegistration.cs" />
<Compile Include="Areas\Second\Controllers\HomeController.cs" />
<Compile Include="Areas\Second\SecondAreaRegistration.cs" />

重新访问页面查看路由,顺序已经改变了（对比上面VS2015里的顺序），可以通过这种方法把最常用的路由调到最前面，提高匹配速度。经测试添加新的Area后，调整的路由顺序不会变回去，可以放心使用。

参考链接：.Net MVC Area Registration Sequence

RouteDebugger 简介

作者地址：ASP.NET Routing Debugger，代码结构图如下：

程序集属性[assembly: PreApplicationStartMethod(typeof(PreApplicationStart), "Start")] 使PreApplicationStart的Start方法在Application_Start方法之前执行，

public static void Start()
        {
            bool flag = Convert.ToBoolean(ConfigurationManager.AppSettings["RouteDebugger:Enabled"]);
            if (flag)
            {
                DynamicModuleUtility.RegisterModule(typeof(RouteDebuggerHttpModule));
            }
        }

最后处理请求的是DebugHttpHandler里的ProcessRequest方法把匹配的路由信息获取出来，代码如下：

  //处理请求
        public void ProcessRequest(HttpContext context)
        {
            HttpRequest request = context.Request;
            if (!this.IsRoutedRequest(request) || context.Response.ContentType == null || !context.Response.ContentType.Equals("text/html", StringComparison.OrdinalIgnoreCase))
            {
                return;
            }
            string text = string.Empty;
            RequestContext requestContext = request.RequestContext;
            if (request.QueryString.Count > )
            {
                RouteValueDictionary routeValueDictionary = new RouteValueDictionary();
                foreach (string text2 in request.QueryString.Keys)
                {
                    if (text2 != null)
                    {
                        routeValueDictionary.Add(text2, request.QueryString[text2]);
                    }
                }
                VirtualPathData virtualPath = RouteTable.Routes.GetVirtualPath(requestContext, routeValueDictionary);
                if (virtualPath != null)
                {
                    text = "<p><label style=\"font-weight: bold; font-size: 1.1em;\">Generated URL</label>: ";
                    text = text + "<strong style=\"color: #00a;\">" + virtualPath.VirtualPath + "</strong>";
                    Route route = virtualPath.Route as Route;
                    if (route != null)
                    {
                        text = text + " using the route \"" + route.Url + "\"</p>";
                    }
                }
            }
            string text3 = string.Empty;
            RouteData routeData = requestContext.RouteData;
            RouteValueDictionary values = routeData.Values;
            RouteBase route2 = routeData.Route;
            string text4 = string.Empty;
            using (RouteTable.Routes.GetReadLock())
            {
                foreach (RouteBase current in RouteTable.Routes)
                {
                    //查询请求与路由是否匹配
                    bool flag = current.GetRouteData(requestContext.HttpContext) != null;

                    string isMatchRequest = string.Format("<span{0}>{1}</span>", DebugHttpHandler.BoolStyle(flag), flag);
                    string url = "n/a";
                    string defaults = "n/a";
                    string constraints = "n/a";
                    string dataTokens = "n/a";
                    Route route3 = this.CastRoute(current);
                    if (route3 != null)
                    {
                        url = route3.Url;
                        defaults = DebugHttpHandler.FormatDictionary(route3.Defaults);
                        constraints = DebugHttpHandler.FormatDictionary(route3.Constraints);
                        dataTokens = DebugHttpHandler.FormatDictionary(route3.DataTokens);
                    }

                 text4 += string.Format("<tr><td>{0}</td><td>{1}</td><td>{2}</td><td>{3}</td><td>{4}</td></tr>", new object[]
                    {
                        isMatchRequest,
                        url,
                        defaults,
                        constraints,
                        dataTokens
                    });
                }
            }
            string text10 = "n/a";
            string text11 = "";
            if (!(route2 is DebugRoute))
            {
                foreach (string current2 in values.Keys)
                {
                    text3 += string.Format("\t<tr><td>{0}</td><td>{1}&nbsp;</td></tr>", current2, values[current2]);
                }
                foreach (string current3 in routeData.DataTokens.Keys)
                {
                    text11 += string.Format("\t<tr><td>{0}</td><td>{1}&nbsp;</td></tr>", current3, routeData.DataTokens[current3]);
                }
                Route route4 = route2 as Route;
                if (route4 != null)
                {
                    text10 = route4.Url;
                }
            }
            else
            {
                text10 = string.Format("<strong{0}>NO MATCH!</strong>", DebugHttpHandler.BoolStyle(false));
            }
            text3 = "text3";
            text10 = "text10";
            text4 = "text4";
            text11 = "text11";
            text = "text";

            context.Response.Write(string.Format("<html>\r\n<div id=\"haackroutedebugger\" style=\"background-color: #fff; padding-bottom: 10px;\">\r\n    <style>\r\n        #haackroutedebugger, #haackroutedebugger td, #haackroutedebugger th {{background-color: #fff; font-family: verdana, helvetica, san-serif; font-size: small;}}\r\n        #haackroutedebugger tr.header td, #haackroutedebugger tr.header th {{background-color: #ffc;}}\r\n    </style>\r\n    <hr style=\"width: 100%; border: solid 1px #000; margin:0; padding:0;\" />\r\n    <h1 style=\"margin: 0; padding: 4px; border-bottom: solid 1px #bbb; padding-left: 10px; font-size: 1.2em; background-color: #ffc;\">Route Debugger</h1>\r\n    <div id=\"main\" style=\"margin-top:0; padding: 0 10px;\">\r\n        <p style=\"font-size: .9em; padding-top:0\">\r\n            Type in a url in the address bar to see which defined routes match it. \r\n            A {{*catchall}} route is added to the list of routes automatically in \r\n            case none of your routes match.\r\n        </p>\r\n        <p style=\"font-size: .9em;\">\r\n            To generate URLs using routing, supply route values via the query string. example: <code>http://localhost:14230/?id=123</code>\r\n        </p>\r\n        <p><label style=\"font-weight: bold; font-size: 1.1em;\">Matched Route</label>: {1}</p>\r\n        {5}\r\n        <div style=\"float: left;\">\r\n            <table border=\"1\" cellpadding=\"3\" cellspacing=\"0\" width=\"300\">\r\n                <caption style=\"font-weight: bold;\">Route Data</caption>\r\n                <tr class=\"header\"><th>Key</th><th>Value</th></tr>\r\n                {0}\r\n            </table>\r\n        </div>\r\n        <div style=\"float: left; margin-left: 10px;\">\r\n            <table border=\"1\" cellpadding=\"3\" cellspacing=\"0\" width=\"300\">\r\n                <caption style=\"font-weight: bold;\">Data Tokens</caption>\r\n                <tr class=\"header\"><th>Key</th><th>Value</th></tr>\r\n                {4}\r\n            </table>\r\n        </div>\r\n        <hr style=\"clear: both;\" />\r\n        <table border=\"1\" cellpadding=\"3\" cellspacing=\"0\">\r\n            <caption style=\"font-weight: bold;\">All Routes</caption>\r\n            <tr class=\"header\">\r\n                <th>Matches Current Request</th>\r\n                <th>Url</th>\r\n                <th>Defaults</th>\r\n                <th>Constraints</th>\r\n                <th>DataTokens</th>\r\n            </tr>\r\n            {2}\r\n        </table>\r\n        <hr />\r\n        <h3>Current Request Info</h3>\r\n        <p>\r\n            AppRelativeCurrentExecutionFilePath is the portion of the request that Routing acts on.\r\n        </p>\r\n        <p><strong>AppRelativeCurrentExecutionFilePath</strong>: {3}</p>\r\n    </div>\r\n</div>", new object[]
            {
                text3,
                text10,
                text4,
                request.AppRelativeCurrentExecutionFilePath,
                text11,
                text
            }));
        }

注：RouteDebugger的源码是通过ILSpy反编译的。

结束语

抽出时间去验证路由顺序是因为两个错误引起的：

1.升级vs2013的mvc4解决方案到vs2015后所有的Area路由失效，返回404错误。以为是vs2015对mvc4的支持不够（刚出来是对mvc4是有点问题），就撤销升级返回vs2013了。

2.在vs2013中添加了一个新的Area，排在了以前的所有路由之后，出现404错误。通过RouteDebugger发现是路由的顺序问题，所以想到上面那个问题应该也是顺序问题，不应该是vs2015的缺陷。

希望这篇文章可以帮助你避免遇到同样的问题，觉着有用就推荐一下吧