Getting null for Json data on controller side - json

Question

I've got this html
<form action="/Cabinet/Inbox" id="frmCabinet" method="post"/>
<input type="hidden" id="hdnSearchOptions" name="searchOptions" />
<input onclick="inbox()"/>
</form>
and I have a function where I gather info from variety of DOM elements and store them in a wrapper object and then do a submit:
function inbox(){
searchOptions={};
searchOptions.SearchText=$('#txtSearch').val();
$('#hdnSearchOptions').val(JSON.stringify(searchOptions));
$('#frmCabinet').submit();
}
Here's the Inbox method on the server side:
public ActionResult(SearchOptions searchOptions){
//code goes here
}
public class SearchOptions{
public string SearchText{get;set;}
//some more properties
}
When submit takes place I get null for the searchOptions parameter. I've tried to set enctype of the form to any possible value, I've even tried appication/json as per this W3C document to no avail. When I look at the value of the hidden element just before submit I see it's like this:
<input type="hidden" id="hdnSearchOptions" name="searchOptions" value="{"SearchText":""}">
So the generated JSON string seems to be fine. What else am I missing? Or isn't this possible at all?

Answer 1

Ok, here's what I ended up doing. After making sure that there's no way to make form encoding "application/json" with normal form submit (contrary to what people say in many SO threads) I decided to use Request.Form to reach the json object constructed on the client side. As #Stephen Muecke stated, I had an option to provide all the input values as parameters, but there are way to many fields and I don't want to mess my action method with lot's of parameters. There's actually a better way than all the rest, which is to pass it inside a ViewModel, but the thing is, in my situation I can't do that because I can't pass a separate ViewModel to a _layout(master) page. So here's the code finally:
public ActionResult(){
var searchOptionsJson = Request.Form["searchOptions"];
if(!string.IsNullOrEmpty(searchOptionsJson))
SearchOptions searchOptions = JsonConvert.DeserializeObject<SearchOptions>(searchOptionsJson);
}