Model Passed into MVC 4 Controller Null - ajax

Question

I'm trying to serialize a form and pass it into a controller as a model. What I'm doing I've done in the past, but it's not working for some reason, so I suspect I am missing something stupid. Perhaps you can find it.
In my controller I have a method:
[HttpPost]
public ActionResult AddShippingLocation(PricingRequestModel model)
{
model.ShippingLocationsModel.Add(new ShippingLocationsModel());
return PartialView("shiplocationPartial", model);
}
In my view I have a script that looks like this:
function AddShippingLocation() {
$.ajax({
data: { model: $('#shippinginfoform').serialize() },
type: "POST",
url: "/PricingRequest/AddShippingLocation",
success: function (response) {
$('#shiplocation-wrapper').html(response);
}
})
}
This is called from a link that gets clicked. Also in the view I have a form that uses this:
#using (Html.BeginForm("AddShippingLocation", "PricingRequest", FormMethod.Post, new { id = "shippinginfoform" }))
{
I put the Addshippinglocation in as the method because I wanted to test to see if the model would be serialized using the built in helper. The model gets passed in properly using Html.BeginForm, it also gets passed in properly when using Ajax.BeginForm. When using jquery.serialize, though, it doesn't get passed in properly. On a side note, I'm using MVC 4. Any ideas? Thanks.
EDIT: Here's the request headers. The top one is a successful post of the model to the method, the bottom is the .serialize() that passes in a null model. I examined the post strings and the are the exact same.
Accept text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Encoding gzip, deflate
Accept-Language en-US,en;q=0.5
Connection keep-alive
Cookie .ASPXAUTH=9F06BF2A7D03211E0D2ACEC26D7A568754C89F8A265EE61D9F8010BB8DF1D97670212F1E853FDE960E87AAC5DC7D364A251F670560448482517DA7C072864F62AC0C5C3E1EE8D375ACC1EA8F4D63CFC3C1DD28BBDCAC945155D15289DCDDA3B540756C0609611C13A438B5FF4CA747219290AFB51F58B8AD35AE40C01D3AFAF8B32ADD7E200148B1E1646400CAC0F116; ASP.NET_SessionId=v3qwt02dn1pd13posl5zzk3n
Host localhost:2652
Referer http://localhost:2652/PricingRequest/custinfo
User-Agent Mozilla/5.0 (Windows NT 6.1; WOW64; rv:16.0) Gecko/20100101 Firefox/16.0
Request Headers From Upload Stream
Content-Length 471
Content-Type application/x-www-form-urlencoded
Accept */*
Accept-Encoding gzip, deflate
Accept-Language en-US,en;q=0.5
Cache-Control no-cache
Connection keep-alive
Content-Length 555
Content-Type application/x-www-form-urlencoded; charset=UTF-8
Cookie .ASPXAUTH=9F06BF2A7D03211E0D2ACEC26D7A568754C89F8A265EE61D9F8010BB8DF1D97670212F1E853FDE960E87AAC5DC7D364A251F670560448482517DA7C072864F62AC0C5C3E1EE8D375ACC1EA8F4D63CFC3C1DD28BBDCAC945155D15289DCDDA3B540756C0609611C13A438B5FF4CA747219290AFB51F58B8AD35AE40C01D3AFAF8B32ADD7E200148B1E1646400CAC0F116; ASP.NET_SessionId=v3qwt02dn1pd13posl5zzk3n
Host localhost:2652
Pragma no-cache
Referer http://localhost:2652/PricingRequest/custinfo
User-Agent Mozilla/5.0 (Windows NT 6.1; WOW64; rv:16.0) Gecko/20100101 Firefox/16.0
X-Requested-With XMLHttpRequest

Answer 1

The request bodies are the same? Somehow, I'm doubtful.
Your ajax request body is going to have
model=....
where .... is your form serialized, which url encodes the inputs, and then the serialization itself is urlencoded. You're urlencoding twice with your ajax request. That doesn't happen with normal form posts, and urlencoding is not idempotent with respect to equal signs.
Try
data: $('#shippinginfoform').serialize(),
If the shippinginfoform form is the same form that's posted, I believe that should post the same data (well, generally: there may be some corner cases with values associated with submit buttons and such.).
I'll admit that there's some chance that I'm wrong, in which case I'll promptly delete this answer.