Ambuiguity in calling action method in mvc

Question

I was creating a sample mvc application and created two action methods (Index) in the Home controller.

public class HomeController : Controller
{
    //
    // GET: /Home/        
    public string Index()
    {
        return Index1();
    }

    public string Index(string message)
    {
        return "hello";
    }
}

And the index is set as the default action in running the application. On running the application I get the below error,

The current request for action 'Index' on controller type 'HomeController' is ambiguous between the following action methods: System.String Index(Int32) on type Mvc4example.Controllers.HomeController System.String Index(System.String) on type Mvc4example.Controllers.HomeController

What I expected is that with out query string it'll invoke the parameterless action method and if there is a query string message is passed then the action method with parameter will get invoked.

Can anyone explain why this behavior?

It is the way MVC works, the parameters are not taken into account for selecting a method. If you want this sort of behaviour, you need to tweak it yourself, for example using an `ActionMethodSelectorAttribute` that looks at the query string and method parameters. — Daniel J.G., Oct 15 '14 at 09:56

score 1 · Answer 1 · answered Oct 15 '14 at 09:57

If you have two methods with same name, Http request attribute must be different

public class HomeController : Controller
{
    [HttpGet]        
    public string Index()
    {
        //...
    }

    [HttpPost]
    public string Index(string message)
    {
        //...
    }
}

dove · Answer 2 · 2014-10-15T09:59:43.823

0

That you have a third action like this

    public string Index(int id)
    {
            return "int";       
    }

would explain this behaviour

of course you don't need the parameterless action either, that's just a special case of the message one, where message is empty

edited Oct 15 '14 at 09:59

answered Oct 15 '14 at 09:54

dove

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No I don't have that action method, but I still I get the same error even after adding that action method too which you mentioned. – Venkatesh Oct 15 '14 at 09:57
you don't need two actions here that are effectively the same, as others have answered already correctly as well, e.g. @Max Brodin – dove Oct 15 '14 at 10:00

score 0 · Accepted Answer · edited May 23 '17 at 11:44

Please check the answer in this post: Routing: The current request for action [...] is ambiguous between the following action methods for more details, but to summarize it:

You can only have a maximum of 2 action methods with the same name on a controller, and in order to do that one must be [HttpPost], and the other must be [HttpGet].

Since both of your methods are GET, you should either rename one of the action methods or move it to a different controller

Ambuiguity in calling action method in mvc

3 Answers3