I am trying to post multiple parameters on a WebAPI controller. One param is from the URL, and the other from the body. Here is the url:
 `/offers/40D5E19D-0CD5-4FBD-92F8-43FDBB475333/prices/`

Here is my controller code:

```
public HttpResponseMessage Put(Guid offerId, OfferPriceParameters offerPriceParameters)
{
    //What!?
    var ser = new DataContractJsonSerializer(typeof(OfferPriceParameters));
    HttpContext.Current.Request.InputStream.Position = 0;
    var what = ser.ReadObject(HttpContext.Current.Request.InputStream);

    return new HttpResponseMessage(HttpStatusCode.Created);
}

```

The content of the body is in JSON:

```
{
    "Associations":
    {
        "list": [
        {
            "FromEntityId":"276774bb-9bd9-4bbd-a7e7-6ed3d69f196f",
            "ToEntityId":"ed0d2616-f707-446b-9e40-b77b94fb7d2b",
            "Types":
            {
                "list":[
                {
                    "BillingCommitment":5,
                    "BillingCycle":5,
                    "Prices":
                    {
                        "list":[
                        {
                            "CurrencyId":"274d24c9-7d0b-40ea-a936-e800d74ead53",
                            "RecurringFee":4,
                            "SetupFee":5
                        }]
                    }
                }]
            }
        }]
    }
}

```

Any idea why the default binding is not able to bind to the `offerPriceParameters` argument of my controller? It is always set to null. But I am able to recover the data from the body using the `DataContractJsonSerializer`.

I also try to use the `FromBody` attribute of the argument but it does not work either.