<strong>一. 在RouteConfig文件中创建并注册一条简单路由：</strong>
Route myroute = new Route("{controller}/{action}", new MvcRouteHandler());
routes.Add("MyRoute", myroute);
使得可以在浏览器中通过http://localhost:xxxxx//Customer/List， 或者http://localhost:26399/Admin/Index 等形式进行访问：
其中Customer表示控制器CustomerController类，List代表该类中的List方法。
除了上述写法，还可以写为：
routes.MapRoute("MyRoute", "{controller}/{action}");
此时，RouteConfig.cs文件中的内容为：
public class RouteConfig
{
public static void RegisterRoutes(RouteCollection routes)
{
//Route myroute = new Route("{controller}/{action}", new MvcRouteHandler());
//routes.Add("MyRoute", myroute);
routes.MapRoute("MyRoute", "{controller}/{action}");
}
}
现在，访问默认URL时，会出现错误，因为默认的URL被表示为"~/"送给路由系统，并不满足任何片段。
<strong>二. 定义默认值</strong>
在MapRoute方法中添加：
routes.MapRoute("MyRoute", "{controller}/{action}", new { action = "Index" });
对于两片段的URL，如/Home/Index，工作原理不变，对于单片段的URL，会给action变量自动赋值Index，也就是说可以请求/Home 。
更近一步，使用：
routes.MapRoute("MyRoute", "{controller}/{action}", new { controller = "Home", action = "Index" });
此时，映射的URL匹配表为：
片段数量=0：
mydomain.com => controller = Home action = Index
片段数量=1：
mydomain.com/Customer => controller=Customer action = Index
片段数量=2：
mydomain.com/Customer/List => controller = Customer action = List
<strong>三.静态URL片段</strong>
并非所有片段都需要可变，如下：
routes.MapRoute("", "Public/{controller}/{action}", new { controller = "Home", action = "Index" });
这个URL模式将只匹配含有3个片段的URL，第一个必须是Public。
若采用下面的方式：
routes.MapRoute("", "X{controller}/{ation}");
这条路由模式匹配的方式为：匹配两片段URL，第一个片段以X打头。此时，访问http://localhost:26399/XHome/Index 即可匹配。
以上三条路由的顺序为：
public static void RegisterRoutes(RouteCollection routes)
{
//Route myroute = new Route("{controller}/{action}", new MvcRouteHandler());
//routes.Add("MyRoute", myroute);
routes.MapRoute("", "X{controller}/{action}");
routes.MapRoute("MyRoute", "{controller}/{action}", new { controller = "Home", action = "Index" });
routes.MapRoute("", "Public/{controller}/{action}", new { controller = "Home", action = "Index" });
}
路由系统根据最先被定义的模式来匹配输入URL，只有在不匹配的情况下，才会继续对下一条路由进行处理，直到找到匹配的一条，或者尝试完所有条目。
因此，<b>必须首先定义较为具体的路由。</b>
可以根据静态片段和默认值为特定的路由创建一个别名。如以前用的是一个ShopController，现在用HomeController代替，则：
public static void RegisterRoutes(RouteCollection routes)
{
//Route myroute = new Route("{controller}/{action}", new MvcRouteHandler());
//routes.Add("MyRoute", myroute);
routes.MapRoute("ShopSchema", "Shop/{action}", new { controller = "Home" });
routes.MapRoute("", "X{controller}/{action}");
routes.MapRoute("MyRoute", "{controller}/{action}", new { controller = "Home", action = "Index" });
routes.MapRoute("", "Public/{controller}/{action}", new { controller = "Home", action = "Index" });
}
第一条路由匹配模式为：两片段URL，第一个片段必须是Shop，action的值为第二个URL片段。但是该模式不含controller的可变片段，因此一定会使用默认值，即/Shop/Index会转换为/Home/Index。
更进一步：
routes.MapRoute("ShopSchema2", "Shop/OldAction", new { controller = "Home", action = "Index" });
<strong>四.定义自定义片段变量</strong>
首先注释之前的所有语句，如下：
public static void RegisterRoutes(RouteCollection routes)
{
//Route myroute = new Route("{controller}/{action}", new MvcRouteHandler());
//routes.Add("MyRoute", myroute);
//routes.MapRoute("ShopSchema2", "Shop/OldAction", new { controller = "Home", action = "Index" });
//routes.MapRoute("ShopSchema", "Shop/{action}", new { controller = "Home" });
//routes.MapRoute("", "X{controller}/{action}");
//routes.MapRoute("MyRoute", "{controller}/{action}", new { controller = "Home", action = "Index" });
//routes.MapRoute("", "Public/{controller}/{action}", new { controller = "Home", action = "Index" });
routes.MapRoute("MyRoute", "{controller}/{action}/{id}", new { controller = "Home", action = "Index", id = "DefaultID" });
}
最后一条路由的URL模式定义了标准的controller和action变量，和一个id的自定义变量。将匹配0~3个片段的URL,第三个片段赋值给id，没有第三个片段时会采用默认值。
可以通过RouteData.Values属性，在Action中访问任何一个片段变量：
public ActionResult CustomVariable()
{
ViewBag.CustomVariable = RouteData.Values["id"];// 此时访问http://localhost:26399/Home/CustomVariable/Hello，CustomVariable中是Hello
return View();
}
此外，如果把Action中的参数的名称变为与URL中的变量相匹配，MVC会把URL中获得的值作为参数传递给Action方法，如：
给CustomVariable这个Action方法加上id参数：
public ActionResult CustomVariable(string id)
{
ViewBag.CustomVariable = id;
return View();
}
URL变为：http://localhost:26399/Home/CustomVariable/5
则，5被当作参数id传递给Action方法：
<html>
<head>
<meta name="viewport" content="width=device-width" />
<title></title>
</head>
<body>
<div>The custom variable is : @ViewBag.CustomVariable</div>
</body>
</html>
此时，返回的View显示：The custom variable is : 5
<strong>4.1 定义可选URL片段</strong>
可选URL片段：用户不需要指定，但又没有指定默认值的片段。
public static void RegisterRoutes(RouteCollection routes)
{
routes.MapRoute("MyRoute", "{controller}/{action}/{id}", new { controller = "Home", action = "Index", id = UrlParameter.Optional });
}
这条匹配的工作模式：
片段=0：xxx.com
=>
controller = Home action = Index
片段=1：xxx.com/Customer
=>
controller = Customer action = Index
片段=2：xxx.com/Customer/List
=>
controller = Customer action = List
片段=3：xxx.com/Customer/List/All
=>
controller = Customer action = List id=All
<strong>4.2 定义可变长路由</strong>
通过制定一个全匹配的片段变量，通过*作为前缀，可以支持可变片段数。
public static void RegisterRoutes(RouteCollection routes)
{
routes.MapRoute("MyRoute", "{controller}/{action}/{id}/{*catchall}", new { controller = "Home", action = "Index", id = UrlParameter.Optional });
}
工作模式为：
/：controller = Home action = Index
/Customer：controller=Customer action=Index
/Customer/List：controller=Customer action=List
/Customer/List/All：controller = Customer action = List Id=All
/Customer/List/All/Delete：controller = Customer action = List Id=All catchall = Delete
/Customer/List/All/Delete/Perm ：controller = Customer action = List Id = All catchall=Delete/Perm
<strong>4.3 按命名空间区分Controller优先顺序</strong>
此时，Controllers文件夹中有一个HomeController类，假如在另一个文件夹中再创建一个HomeController类，访问时会报错：
报错信息png
解决方法如下：
public static void RegisterRoutes(RouteCollection routes)
{
routes.MapRoute("MyRoute", "{controller}/{action}/{id}/{*catchall}",
new { controller = "Home", action = "Index", id = UrlParameter.Optional },
new[] { "UrlsAndRoutes.AdditionalControllers" });
}
以上代码告诉MVC框架，先考察URLsAndRoutes.AdditionalControllers命名空间。
注意：一条路由中的命名空间具有相等优先级，若：
public static void RegisterRoutes(RouteCollection routes)
{
routes.MapRoute("MyRoute", "{controller}/{action}/{id}/{*catchall}",
new { controller = "Home", action = "Index", id = UrlParameter.Optional },
new[] { "UrlsAndRoutes.AdditionalControllers", "UrlsAndRoutes.Controllers" });
}
会报同样的错误。
如果希望对某个命名空间中的某个Controller优先，又需要解析另一个命名空间中的其他Controller，需要创建多条路由：
public static void RegisterRoutes(RouteCollection routes)
{
routes.MapRoute("AddControllerRoute", "Home/{action}/{id}/{*catchall}",
new { controller = "Home", action = "Index", id = UrlParameter.Optional },
new[] { "URLsAndRoutes.AdditionalControllers" });
routes.MapRoute("MyRoute", "{controller}/{action}/{id}/{*catchall}",
new { controller = "Home", action = "Index", id = UrlParameter.Optional },
new[] { "URLsAndRoutes.Controllers" });
}
此时，若用户的第一个片段为Home，会运用第一条路由，并以AdditionalControllers文件夹中的Controller为目标。除此之外的其它请求，使用Controllers文件夹中的Controller处理。
还可以在所指定的命名空间中找不到匹配时，不在搜索其它地方，如下：
Route MyRoute = routes.MapRoute("AddControllerRoute", "Home/{action}/{id}/{*catchall}",
new { controller = "Home", action = "Index", id = UrlParameter.Optional },
new[] { "UrlsAndRoutes.AdditionalControllers" });
MyRoute.DataTokens["UseNamespaceFallback"] = false;
<strong>五.约束路由</strong>
<strong>5.1 用正则表达式约束路由</strong>
public static void RegisterRoutes(RouteCollection routes)
{
routes.MapRoute("MyRoute", "{controller}/{action}/{id}/{*catchall}",
new { controller = "Home", action = "Index", id = UrlParameter.Optional },
new { controller = "^H.*" },
new[] { "URLsAndRoutes.Controllers" });
}
该路由匹配controller变量值以“H”打头的URL。
注意，首先运用默认值，再检查约束。因此，若请求的URL是 / ，会把默认值“Home”运用于controller，然后再检查约束。
<strong>5.2 将一条路由约束到一组指定的值</strong>
可以使用 | 把一条路由约束到一组指定的片段变量值
public static void RegisterRoutes(RouteCollection routes)
{
routes.MapRoute("MyRoute", "{controller}/{action}/{id}/{*catchall}",
new { controller = "Home", action = "Index", id = UrlParameter.Optional },
new { controller = "^H.*", action = "^Index$|^About$"},
new[] { "URLsAndRoutes.Controllers" });
}
这条约束允许这个路由只匹配action片段的值为“Index”或者“About”的URL。
<strong>5.3 使用HTTP方法约束路由</strong>
可以约束路由，使得它们只匹配指定的HTTP方法进行请求的URL。
public static void RegisterRoutes(RouteCollection routes)
{
routes.MapRoute("MyRoute", "{controller}/{action}/{id}/{*catchall}",
new { controller = "Home", action = "Index", id = UrlParameter.Optional },
new
{
controller = "^H.*",
action = "^Index$|^About$",
httpMethod = new HttpMethodConstraint("Get")
},
new[] { "URLsAndRoutes.Controllers" });
}
上述语法中，httpMethod可以是任何名字，只要是一个HttpMethodConstraint实例即可。
也可以使用类型和值约束，如下：
public static void RegisterRoutes(RouteCollection routes)
{
routes.MapRoute("MyRoute", "{controller}/{action}/{id}/{*catchall}",
new { controller = "Home", action = "Index", id = UrlParameter.Optional },
new
{
controller = "^H.*",
action = "^Index$|^About$",
httpMethod = new HttpMethodConstraint("Get"),
id = new RangeRouteConstraint(10, 20)
},
new[] { "URLsAndRoutes.Controllers" });
}
这条路由使用了RangeRouteConstraint类，检查提供的片段变量的值是否是10到20中的一个有效的int类型值。
约束类集合.png
假设要确保路由将仅仅匹配包含字母字符并且至少含有6个字符的字符串值：
routes.MapRoute("MyRoute", "{controller}/{action}/{id}/{*catchall}",
new { controller = "Home", action = "Index", id = UrlParameter.Optional },
new
{
controller = "^H.*",
action = "^Index$|^About$",
httpMethod = new HttpMethodConstraint("Get"),
id = new CompoundRouteConstraint(new IRouteConstraint[]
{
new AlphaRouteConstraint(),
new MinLengthRouteConstraint(6)
})
},
new[] { "URLsAndRoutes.Controllers" });
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