Self-hosted Web API - Post Param null - asp.net-web-api

Question

I'm trying to set up a simple test to make a POST request to my self-hosted Web-API server.
var config = new HttpSelfHostConfiguration(new Uri(baseAddress));
// add a route
config.Routes.MapHttpRoute(name: "DefaultApi",
routeTemplate: "api/{controller}/{id}",
defaults: new { id = RouteParameter.Optional }
);
server = new HttpSelfHostServer(config);
server.OpenAsync().Wait();
I added a Controller:
public class PayloadController : ApiController
{
public string Get()
{
return "Hello from GET";
}
public HttpResponseMessage PostItem(Payload payload)
{
// payload
//...
}
}
And I do have the corresponding model (making sure it contains properties):
public class Payload
{
public string Date { get; set; }
public string Command { get; set; }
}
I'm using Rest Console on Chrome to test the server, getting correct results for the GET in my controller.
Issueing the following request as POST:
Request Url: http://localhost:8080/api/payload
Request Method: POST
Params: {
"Date": "2012.09.26",
"Command": "Hello"
}
EDIT: Content-Type is set to application/json and encoding to UTF-8
Setting a break-point at the controller shows that the POST params are not correctly deserialized into an Paylod object, the param is null.
What am I possibly missing?

Answer 1

You need to specify the request Content-Type as application/json
Edit
Complete response with info from the comments below:
If you are using REST console's "request parameters" instead of "request payload raw body" it will not generate JSON out of them even when you specify application/json.
You need to paste raw JSON into the raw body field like this: http://screencast.com/t/iRWZqv91
{
"Date": "2012.09.26",
"Command": "Hello"
}

Answer 2

If you are receiving a null post parameter to your controller you need to create a constructor with 0 parameters in your model.
Greetings