OK. Now I understand where you have the problem. You use Newtonsoft.Json to serialize the data, but your web service don't know this and try to serialize the data one more time. So you have probably twice serialized string. If the oririnal string was My string. JSON seirialized string will be “My string“. If the original string was “MyString” then serialized version will have escaped quotas: “MyString”. So after deserialization of a string you have allways the type string in Javascript instead of an object.
If you will just use standard Microsoft serialization you need only include
[WebMethod, ScriptMethod(ResponseFormat = ResponseFormat.Json)]
before the web method GetProvinces and return just an instance of the class JqGridData. Web service will serialize the data yourself, but include all data inside the property “d”: {d:{..}}.
I uploaded a working test program which full simulate your first data under http://www.ok-soft-gmbh.com/jqGrid/WebServicesPostToJqGrid.zip.
If you do need to use a custon JSON serialization like Newtonsoft.Json I should better use WCF instead of ASMX. The code is exactly so simple like ASMX, but you have much more flefibility. If your WCF web method return Stream or Message type, than you can return any type of data: any custom serialized JSON data, JPEG and so on. You can also stream the data if needed.
See http://msdn.microsoft.com/en-us/library/ms789010.aspx, http://stackoverflow.com/questions/3078397/returning-raw-json-string-in-wcf/3079326#3079326 and http://stackoverflow.com/questions/3118504/how-to-set-json-net-as-the-default-serializer-for-wcf-rest-service/3131413#3131413 for more information.
Regards
Oleg
.
