AJAX和DATATABLES

Question

When i call Ajax request, network request window show that there is an error in the AJAX response.

Message:    Primitiva JSON non valida: idParrocchia.
<br>StackTrace in:System.Web.Script.Serialization.JavaScriptObjectDeserializer.DeserializePrimitiveObject() in System.Web.Script.Serialization.JavaScriptObjectDeserializer.DeserializeInternal(Int32 depth) in System.Web.Script.Serialization.JavaScriptObjectDeserializer.BasicDeserialize(String input, Int32 depthLimit, JavaScriptSerializer serializer) in System.Web.Script.Serialization.JavaScriptSerializer.Deserialize(JavaScriptSerializer serializer, String input, Type type, Int32 depthLimit) in System.Web.Script.Serialization.JavaScriptSerializer.Deserialize[T](String input) in System.Web.Script.Services.RestHandler.GetRawParamsFromPostRequest(HttpContext context, JavaScriptSerializer serializer) in System.Web.Script.Services.RestHandler.GetRawParams(WebServiceMethodData methodData, HttpContext context) in System.Web.Script.Services.RestHandler.ExecuteWebServiceCall(HttpContext context, WebServiceMethodData methodData)
    ExceptionType   System.ArgumentException

The code is

"ajax": {
    "contentType": "application/json; charset=utf-8",
    "type": "POST",
    "url": "ajax/WSHome.asmx/GetNewsList",
    "data": {idParrocchia: idParr},
    "dataType": "json",
    'dataSrc': '',
    'cache': false,
    "success": successAjax()
},

Thanks, Luca