Invalid JSON privilige draw. in AJAX call to Webmethod in ASP.NET webforms using jquery Datatables

Question

I'm trying to implement server-side processing for jquery Datatables.NET in my ASP.NET webforms test application.

Using following code: Jquery :

$(document).ready(start);

function start(){
$('#PersonsTable').DataTable({
        "processing": true,
        "serverSide": true,
        "ajax": {
            "url": "/AjaxTest.aspx/GetPersonsHttp",
            "type" : "POST",
            "dataType": "json",
            "contentType": "application/json; charset=UTF-8"
        },
        "columns": [
            { "data": "FirstName" },
            { "data": "Name" }
        ]
    });
};

C# (in my AjaxTest.aspx.cs):

[WebMethod]
public static Person GetPersonsHttp()
{
    Person me = new Person() { FirstName = "John", Name = "Doe" };
    return me;
}

Class Person:

public class Person
    {
        public string Name { get; set; }
        public string FirstName { get; set; }

        public override string ToString()
        {
            return string.Format("{0} {1}", this.FirstName, this.Name);
        }

    }

My AjaxTest.aspx looks like this:

<table class="table table-hover table-striped" id="PersonsTable">
                <thead>
                    <tr>
                        <th>Vooraam</th>
                        <th>Naam</th>
                    </tr>
                </thead>
                <tbody>

                </tbody>
            </table>

Eventually I'm getting following error:

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

Somebody who knows what I'm doing wrong here?

You should refer to that question http://stackoverflow.com/questions/2445874/invalid-json-primitive-in-ajax-processing — Nicolas, Feb 23 '17 at 13:40
OK but this doesn't answer the question. I can't find a working example with datatables / ajax / c# (asp.net) — Bert Levrau, Feb 23 '17 at 13:41
try to add `[ScriptMethod(UseHttpGet = true, ResponseFormat = ResponseFormat.Json)]` on top of your static method — Elmer Dantas, Feb 23 '17 at 13:46
@ElmerDantas can you please give this as a answer, so I can accept this as the solution! the 3 things I changed. "type" : "POST", to "type" : "Get", added [ScriptMethod(UseHttpGet = true, ResponseFormat = ResponseFormat.Json)] and made my function reurn a list in stead of 1 item. Like this public static List GetPersonsHttp() — Bert Levrau, Feb 23 '17 at 14:42

score 1 · Accepted Answer · answered Feb 23 '17 at 14:45

1

Try to add [ScriptMethod(UseHttpGet = true, ResponseFormat = ResponseFormat.Json)] on top of your static method.

answered Feb 23 '17 at 14:45

Elmer Dantas

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Invalid JSON privilige draw. in AJAX call to Webmethod in ASP.NET webforms using jquery Datatables

1 Answers1