How can I avoid AmbiguousMatchException between two controller actions?

Question

I have two controller actions with the same name but with different method signatures. They look like this:

    //
    // GET: /Stationery/5?asHtml=true
    [AcceptVerbs(HttpVerbs.Get)]
    public ContentResult Show(int id, bool asHtml)
    {
        if (!asHtml)
            RedirectToAction("Show", id);

        var result = Stationery.Load(id);
        return Content(result.GetHtml());
    }

    //
    // GET: /Stationery/5
    [AcceptVerbs(HttpVerbs.Get)]
    public XmlResult Show(int id)
    {
        var result = Stationery.Load(id);
        return new XmlResult(result);
    }

My unit tests have no issue with calling one or the other controller action, but my test html page throws a System.Reflection.AmbiguousMatchException.

<a href="/Stationery/1?asHtml=true">Show the stationery Html</a>
<a href="/Stationery/1">Show the stationery</a>

What needs to change to make this work?

score 12 · Accepted Answer · answered Apr 09 '09 at 04:28

12

Just have one method like this.

[AcceptVerbs(HttpVerbs.Get)]
public ActionResult Show(int id, bool? asHtml)
{
    var result = Stationery.Load(id);

    if (asHtml.HasValue && asHtml.Value)
        return Content(result.GetHtml());
    else
        return new XmlResult(result);
}

answered Apr 09 '09 at 04:28

Schotime

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I originally had something like this, but I didn't want to change all my unit tests to cast the ActionResult to the appropriate type (as well as add the null to the signature). However, this is probably the best way as I don't care for the other options. Answer +1 – Sailing Judo Apr 09 '09 at 12:30
Note that you can't overload an action. http://stackoverflow.com/questions/436866/can-you-overload-controller-methods-in-asp-net-mvc – Samuel Jun 18 '13 at 17:29

score 6 · Answer 2 · edited May 23 '17 at 11:58

6

Heres a link you may find userful. It talks about overloading the MVC Controllers.

edited May 23 '17 at 11:58

Community

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answered Apr 08 '09 at 22:53

Brandon

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Gave this a +1 the link was useful in making my decision. – Sailing Judo Apr 09 '09 at 12:31

J.W. · Answer 3 · 2009-04-08T23:19:07.377

1

There are two ways to address this:

1> Change the method name. 2> Provide different ActionName attributes to the two methods. You can define your own attribute.

edited Apr 08 '09 at 23:19

answered Apr 08 '09 at 23:06

J.W.

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Gave this a +1 because it would work, it just didn't suit my needs. – Sailing Judo Apr 09 '09 at 12:30

score 0 · Answer 4 · answered Feb 17 '10 at 01:12

To overcome this problem you can write an ActionMethodSelectorAttribute that examines the MethodInfo for each action and compares it to the posted Form values and then rejects any method for which the form values don't match (excluding the button name, of course).

Here's an example:- http://blog.abodit.com/2010/02/asp-net-mvc-ambiguous-match/

You could also make a simpler ActionMethodSelectorAttribute which looks only at the submit button name but that would tie your controller and view more closely.

score 0 · Answer 5 · answered Apr 08 '09 at 23:09

0

There is the ActionName attribute. Take a look.

answered Apr 08 '09 at 23:09

Daniel A. White

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How can I avoid AmbiguousMatchException between two controller actions?

5 Answers5

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