"Invalid JSON primitive" in Ajax processing

Question

I am getting an error in an ajax call from jQuery.

Here is my jQuery function:

function DeleteItem(RecordId, UId, XmlName, ItemType, UserProfileId) {     var obj = {         RecordId: RecordId,         UserId: UId,         UserProfileId: UserProfileId,         ItemType: ItemType,         FileName: XmlName     };     var json = Sys.Serialization.JavaScriptSerializer.serialize(obj);      $.ajax({         type: "POST",         url: "EditUserProfile.aspx/DeleteRecord",         data: json,         contentType: "application/json; charset=utf-8",         dataType: "json",         async: true,         cache: false,         success: function(msg) {             if (msg.d != null) {                 RefreshData(ItemType, msg.d);             }         },         error: function(XMLHttpRequest, textStatus, errorThrown) {             alert("error occured during deleting");         }     }); } 

and this is my WebMethod:

[WebMethod] public static string DeleteRecord(Int64 RecordId, Int64 UserId, Int64 UserProfileId, string ItemType, string FileName) {     try {         string FilePath = HttpContext.Current.Server.MapPath(FileName);          XDocument xmldoc = XDocument.Load(FilePath);         XElement Xelm = xmldoc.Element("UserProfile");         XElement parentElement = Xelm.XPathSelectElement(ItemType + "/Fields");          (from BO in parentElement.Descendants("Record")          where BO.Element("Id").Attribute("value").Value == RecordId.ToString()          select BO).Remove();         XDocument xdoc = XDocument.Parse(Xelm.ToString(), LoadOptions.PreserveWhitespace);         xdoc.Save(FilePath);          UserInfoHandler obj = new UserInfoHandler();         return obj.GetHTML(UserId, UserProfileId, FileName, ItemType, RecordId, Xelm).ToString();     } catch (Exception ex) {         HandleException.LogError(ex, "EditUserProfile.aspx", "DeleteRecord");     }     return "success"; } 

Can anybody please tell me what's wrong in my code?

I am getting this error:

{     "Message":"Invalid JSON primitive: RecordId.",     "StackTrace":"        at System.Web.Script.Serialization.JavaScriptObjectDeserializer.DeserializePrimitiveObject()        at System.Web.Script.Serialization.JavaScriptObjectDeserializer.DeserializeInternal(Int32 depth)        at System.Web.Script.Serialization.JavaScriptObjectDeserializer.BasicDeserialize(String input, Int32 depthLimit, JavaScriptSerializer serializer)        at System.Web.Script.Serialization.JavaScriptSerializer.Deserialize(JavaScriptSerializer serializer, String input, Type type, Int32 depthLimit)        at System.Web.Script.Serialization.JavaScriptSerializer.Deserialize[T](String input)        at System.Web.Script.Services.RestHandler.GetRawParamsFromPostRequest(HttpContext context, JavaScriptSerializer serializer)        at System.Web.Script.Services.RestHandler.GetRawParams(WebServiceMethodData methodData, HttpContext context)        at System.Web.Script.Services.RestHandler.ExecuteWebServiceCall(HttpContext context, WebServiceMethodData methodData)",     "ExceptionType":"System.ArgumentException" } 

Answer 1

Just a guess what does the variable json contain after

var json = Sys.Serialization.JavaScriptSerializer.serialize(obj);? 

If it is a valid json object like {"foo":"foovalue", "bar":"barvalue"} then jQuery might not send it as json data but instead serialize it to foor=foovalue&bar=barvalue thus you get the error "Invalid JSON primitive: foo"

Try instead setting the data as string

$.ajax({     ...     data: '{"foo":"foovalue", "bar":"barvalue"}', //note the additional quotation marks     ... }) 

This way jQuery should leave the data alone and send the string as is to the server which should allow ASP.NET to parse the json server side.