Question

Background

I am coding an API layer in C# using MVC 4 Web API Project (ASP.NET).

I have written a test action in my controller like this:

[System.Web.Mvc.HttpPost]
public string TestAction(FormCollection fc)
{
    return "test";
}

I am using Poster in FireFox to test a form post:

• content-type is set to application/x-www-form-urlencoded
• Body from parameters is set to foo=bar&bar=foo

Here is my route:

RouteTable.Routes.MapHttpRoute("PostDefault", "{controller}/{action}");

Question

I am able to hit the controller with no problem when posting a url and parameters from Poster, but if I put a breakpoint on return "test"; and then hover over the FormCollection that is passed in (fc) It shows that an empty array of strings was passed in rather than my values (e.g. string[0]).

I have done this loads of times using jQuery $.post() on the client with no problems receiving the form collection.

What is it failing in this case?

Thanks,

Matt

Answer 1

It seems that this is an action defined inside an API controller (ApiController). If this is the case you cannot use FormCollection. This is used for normal controller actions, not API controllers (personally I don’t use it even in normal controller actions but that’s another topic, see the next paragraph to understand what I am using instead).

You should define a view model:

public class MyViewModel
{
    public string Foo { get; set; }
    public string Bar { get; set; }
}

and then have your controller action take this view model as parameter:

public class TestController: ApiController
{
    [System.Web.Http.HttpPost]
    public string TestAction(MyViewModel model)
    {
        return "test";
    }
}

Notice that the correct attribute for an API controller is [System.Web.Http.HttpPost] and not [System.Web.Mvc.HttpPost] as in your code.

Also I would recommend you sticking to RESTful conventions:

RouteTable.Routes.MapHttpRoute("PostDefault", "{controller}");

and then:

public class TestController: ApiController
{
    public string Post(MyViewModel model)
    {
        return "test";
    }
}

Now the HTTP Verb (POST in this case) determines the controller action to be invoked:

POST /test
Server: http://example.com
Content-Type: application/x-www-form-urlencoded
Content-Length: 15
Connection: close

foo=bar&bar=foo