"The type or namespace name 'Route' could not be found" using "attribute routing"

Question

Just trying to splice some code from one working project to another. The "from" project uses "attribute routing" where you embed [Route(…)] directives in the Web API controller modules to indicate what HTTP message should route to what service routine.

Works fine in the "from" project, but in the "to" project I get the build error "The type or namespace name 'Route' could not be found (are you missing a using directive or an assembly reference?)"

I've tried copying essentially all of the using statements from the "from" project to the "to" project, but that has no apparent effect. None of the MS documentation suggests that a NuGet package is required (or even a using statement). Both projects are supposedly ASP.NET MVC 4.

(And, yes, I updated WebApiConfig.cs with the config.MapHttpAttributeRoutes(); statement.)

Any ideas??

Solution 1

Attribute Routing is native in ASP.NET MVC 5, or later, and ASP.NET Web API 2.

For previous versions you can use one of the packages from the AttributeRouting project that allows to use attribute routing in previous version of ASP.NET MVC, and Web API. The availabe nuget packages are:

• Install-Package AttributeRouting (for MVC)
• Install-Package AttributeRouting.WebApi (for Web API)
• Install-Package AttributeRouting.WebApi.Hosted (for self-hosted Web API)

Please, be aware that the namespaces of attribute routing are different for each version, so you must review the project soruces code, or browse the .dll included by the installed package, to find out the right namespace, and change your using accordingly. For example:

using AttributeRouting.Web.Http;

Solution 2

This comment from Vedran Mandić solved the problem for me. I'm re-posting it here because I think it should be the answer (or at least a answer).

I did an 'Update-Package Microsoft.AspNet.WebApi.WebHost -reinstall' and it worked. Funny this happens after getting the latest version on different PCs from TFS. I guess this happens because of nuget packages not working properly with the versioning system

Solution 3

In my case, in web api project there were two using references:

using System.Web.Http;
using System.Web.Mvc; 

As soon as I removed System.Web.Mvc, the error was gone.

Comments

[Hot Licks]

Unfortunately, installing the AttributeRouting package does not make the messages go away. (I have a "using System.Web.Http.Routing;" in the module.)

[JotaBe]

That's logical. The namespace is different. You must get sure which version of Web API are using. The attributes to use depend on versions (of MVC and Web API ) and if it's Web API, self hosted Web API or MVC.

[Leandro Bardelli]

this rocks. Same problem here with TFS and nuget

[Ads]

Thanks so much for the tip, but I personally hate this kind of fix. It usually involves lots of head banging, wasted time and frustration.

[sal]

Still getting error. [RoutePrefix("xxx")] taking referance but still [Route("xxx")] unavalible.

[Thom Parkin]

Me too. UNTIL I followed the advice from ClearCloud8 (above)

[Coyttl]

Oddly - updated VS2019 from 16.7.5 to 16.8.2 (latest) and had to do this. Worked like a charm

[Dominik S]

Thel link is dead, so I provide link to GH: github.com/mccalltd/AttributeRouting