How can I create a route constraint of type System.Guid?

Question

Can anyone point me in the right direction on how to map a route which requires two guids?

ie. http://blah.com/somecontroller/someaction/{firstGuid}/{secondGuid}

where both firstGuid and secondGuid are not optional and must be of type system.Guid?

Answer 1

Create a RouteConstraint like the following:

public class GuidConstraint : IRouteConstraint {  public bool Match(HttpContextBase httpContext, Route route, string parameterName, RouteValueDictionary values, RouteDirection routeDirection) {     if (values.ContainsKey(parameterName))     {         string stringValue = values[parameterName] as string;          if (!string.IsNullOrEmpty(stringValue))         {             Guid guidValue;              return Guid.TryParse(stringValue, out guidValue) && (guidValue != Guid.Empty);         }     }      return false; }} 

Next when adding the route :

routes.MapRoute("doubleGuid", "{controller}/{action}/{guid1}/{guid2}", new { controller = "YourController", action = "YourAction" }, new { guid1 = new GuidConstraint(), guid2 = new GuidConstraint() }); 

Answer 2

For MVC 5 there is already implemented the GuidRouteConstraint Class:
https://msdn.microsoft.com/en-us/library/system.web.mvc.routing.constraints.guidrouteconstraint(v=vs.118).aspx

Full list of available MVC constraints:
https://msdn.microsoft.com/en-us/library/system.web.mvc.routing.constraints(v=vs.118).