Web API throws exception after installing AttributeRouting - invalidoperationexception

Question

I developed a simple VB .NET Web API project using .NET 4.5
This project was working perfectly fine, but I decided to install the AttributeRouting nuget package. After installing this package every function seems to raise the following exception:
The constraint entry 'inboundHttpMethod' on the route with route
template 'Company' must have a string value or be of a type which
implements 'IHttpRouteConstraint'.
In this message 'Company' is the route name to a simple GET method that simple returns one object. Every route results in this error message. The stacktrace is:
[InvalidOperationException: The constraint entry 'inboundHttpMethod'
on the route with route template 'Company/{Id}' must have a string
value or be of a type which implements 'IHttpRouteConstraint'.]
System.Web.Http.Routing.HttpRoute.ProcessConstraint(HttpRequestMessage
request, Object constraint, String parameterName,
HttpRouteValueDictionary values, HttpRouteDirection routeDirection)
+346 System.Web.Http.Routing.HttpRoute.ProcessConstraints(HttpRequestMessage
request, HttpRouteValueDictionary values, HttpRouteDirection
routeDirection) +201
System.Web.Http.Routing.HttpRoute.GetRouteData(String virtualPathRoot,
HttpRequestMessage request) +430
AttributeRouting.Web.Http.Framework.HttpAttributeRoute.GetRouteData(String
virtualPathRoot, HttpRequestMessage request) +250
System.Web.Http.WebHost.Routing.HttpWebRoute.GetRouteData(HttpContextBase
httpContext) +191
System.Web.Routing.RouteCollection.GetRouteData(HttpContextBase
httpContext) +233
System.Web.Routing.UrlRoutingModule.PostResolveRequestCache(HttpContextBase
context) +60
System.Web.Routing.UrlRoutingModule.OnApplicationPostResolveRequestCache(Object
sender, EventArgs e) +82
System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
+136 System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +69
I found the following thread which describes my problem: https://github.com/mccalltd/AttributeRouting/issues/191
Unfortunately, this fix does not seem to help: https://github.com/mccalltd/AttributeRouting/issues/191#issuecomment-13814025
Any ideas on how to fix this?

Answer 1

In your case, I definitely feel like this issue is related with in memory hosting and do have a solution in the link that you mention above.
After updating to MVC 5 I came across this issue and following the workout in this link which ultimately helped me out.
Here is how I did it.
In global.ascx page, I have the following:
AttributeRoutingHttpConfig.RegisterRoutes(GlobalConfiguration.Configuration.Routes);
In AttributeRoutingHttpConfig class, I replaced the code
routes.MapHttpAttributeRoutes();
with
routes.MapHttpAttributeRoutes(cfg =>
{
cfg.InMemory = true;
cfg.AutoGenerateRouteNames = true;
cfg.AddRoutesFromAssemblyOf<Your_API_Controller>();
});
You can overwrite Your_API_Controller with any of your ApiController class. (Yes, don't know why but any api controller you want works ;) )
Hope this helps,