在MVC 6中进行路由 [英] Routing in MVC 6
问题描述
我有2种方法的超级简单控制器:
I have a super simple controller with 2 methods:
public IActionResult Users(long id)
{
return Json(new { name = "Example User" });
}
public IActionResult Users()
{
return Json(new { list = new List<User>() });
}
一个选择所有用户,另一个选择返回所有用户.在Web API 2中,我可以使用以下路由,并且一切正常:
One to select all users and the other to return all users. In web api 2 I could user the following route and everything worked fine:
config.Routes.MapHttpRoute(
name: "Users",
routeTemplate: "v1/Users",
defaults: new { action = "Users", controller = "Users" },
constraints: null,
handler: new TokenValidationHandler() { InnerHandler = new HttpControllerDispatcher(config) }
);
我在startup.cs中设置了以下路由:
I have the following routes setup in startup.cs:
app.UseMvc(routes =>
{
routes.MapRoute(name: "User_Default", template: "v1/{controller=Users}/{action=Users}/{id?}");
});
但是这给了我AmbiguousActionException: Multiple actions matched. The following actions matched route data and had all constraints satisfied
我在做什么错了?
推荐答案
在您原始的webapi代码中,您使用的是Routes.MapHttpRoute
,它添加了webapi特定的路由.这与MVC路由不同,后者不会考虑操作中的参数,例如,如果您使用Routes.MapRoute
,则在MVC 5中也会遇到相同的问题.
In your original webapi code, you were using Routes.MapHttpRoute
which adds webapi specific routes. This is different from an MVC route which won´t take into account the parameters in the action, for instance you would have the same problem in MVC 5 if you were using Routes.MapRoute
.
由于要使用routes.MapRoute
添加标准MVC路由,因此MVC 6代码中也发生了同样的情况.在这两种情况下,框架都会找到2个与同一路由匹配的控制器动作,而没有其他约束.需要一些帮助才能选择这两个动作之一.
The same thing is happening in your MVC 6 code, since you are adding a standard MVC route using routes.MapRoute
. In both cases the framework is finding 2 controller actions matching the same route with no additional constraints. It needs some help in order to select one of those 2 actions.
消除api操作歧义的最简单方法是使用属性路由而不是定义路由,如
The easiest way to disambiguate the api actions would be using attribute routing instead of defining a route, as in this example:
[Route("v1/[controller]")]
public class UsersController : Controller
{
[HttpGet("{id:int}")]
public IActionResult Users(long id)
{
return Json(new { name = "Example User" });
}
public IActionResult Users()
{
return Json(new { list = new[] { "a", "b" } });
}
}
还有其他选项可以让您更改MVC 6中MVC路由的行为.您可以创建自己的IActionConstraint
属性以强制具有或不具有给定参数.这样,其中一个操作就需要在路由中使用id参数,而其他操作则不需要具有id参数(警告,未经测试的代码):
There are other options that would let you change the behaviour of the MVC routing in MVC 6. You could create your own IActionConstraint
attribute to enforce having or not a given parameter. That way one of those actions requires an id parameter in the route while the other requires not to have an id parameter (Warning, untested code):
public class UsersController : Controller
{
[RouteParameterConstraint("id", ShouldAppear=true)]
public IActionResult Users(long id)
{
return Json(new { name = "Example User" });
}
[RouteParameterConstraint("id", ShouldNotAppear=true)]
public IActionResult Users()
{
return Json(new { list = new[] { "a", "b" } });
}
}
public class RouteParameterConstraintAttribute : Attribute, IActionConstraint
{
private routeParameterName;
public RouteParameterConstraintAttribute(string routeParameterName)
{
this.routerParamterName = routerParameterName;
}
public int Order => 0;
public bool ShouldAppear {get; set;}
public bool ShouldNotAppear {get; set;}
public bool Accept(ActionConstraintContext context)
{
if(ShouldAppear) return context.RouteContext.RouteData.Values["country"] != null;
if(ShouldNotAppear) return context.RouteContext.RouteData.Values["country"] == null;
return true;
}
}
处理webapi 2样式控制器的更好选择是将约定添加到MVC管道中.这正是Microsoft.AspNet.Mvc.WebApiCompatShim
为帮助迁移webapi 2控制器所做的工作.您可以在此处.检查
A better option to deal with webapi 2 style controllers would be adding conventions into the MVC pipeline. This is exactly what the Microsoft.AspNet.Mvc.WebApiCompatShim
is doing to help migrating webapi 2 controllers. You can see the conventions added here. Check this guide for a quick overview of this package.
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