Ajax call returning 500 internal server error

I am trying to make a google map appear on my web page without using another page load. I keep getting an error when I try to call a web method that i have. Here is the code that I use to call the web method:

HTML

<form id="cSharpServerSideForm" runat="server">
        <asp:ScriptManager ID="_scriptManager" runat="server">
          <Services>
            <asp:ServiceReference Path="WebServices/Ajax.asmx" />
          </Services>
        </asp:ScriptManager>
    </form>

Javascript:

//To get webservice (located in document.ready)
vars.service = MyMap.WebServices.Ajax;

getInputForCenterMap = function () {
//The Jarray used
var jArrayCoords;  

var ResponseArray;

//Input values
tCity = "";开发者_开发问答
tState = "";
tZip = "";

//Gets input values
tCity = $('#cityInput').val();
tState = $('#stateInput').val();
tZip = $('#zipInput').val();

//Checks to see inputs entered
if (tZip == "" && tState == "" && tCity == "") { //Nothing entered
    //Error message
    $('#cszErrorMessage').html("Please enter a city/state or zip code");
} else {
    //In case of errors
    try {
        //Check what has been entered
        if (tZip == "") {    //City and state entered
            //Init array call
            jArrayCoords = new Array(2);
            //Adds city and state to array
            jArrayCoords[0] = tCity;
            jArrayCoords[1] = tState;

        } else {    //Zip entered
            //Init array call
            jArrayCoords = new Array(1);
            //Adds city and state to array
            jArrayCoords[0] = tZip;
        }

        //Calls web service
        vars.service.getMapCenterCoords(jArrayCoords, function (response) {
            //Turns response into a jarray
            responseArray = new Array(response);
            //Rest of code
        });

    } catch (error) {
        //Error message
    }
}

C#

  public double[] getMapCenterCoords(JArray userLocationInformation)
    {
      //Method information
    }

I get there error as soon as the c# method is called. here is the error message:

500 Internal Server Error

"System.ArgumentException"

"Argument is not a JToken."

" at Newtonsoft.Json.Linq.JContainer.EnsureValue(Object value) at Newtonsoft.Json.Linq.JContainer.System.Collections.IList.Add(Object value) at System.Web.Script.Serialization.ObjectConverter.AddItemToList(IList oldList, IList newList, Type elementType, JavaScriptSerializer serializer, Boolean throwOnError) at System.Web.Script.Serialization.ObjectConverter.ConvertListToObject(IList list, Type type, JavaScriptSerializer serializer, Boolean throwOnError, IList& convertedList) at System.Web.Script.Serialization.ObjectConverter.ConvertObjectToTypeInternal(Object o, Type type, JavaScriptSerializer serializer, Boolean throwOnError, Object& convertedObject) at System.Web.Script.Serialization.ObjectConverter.ConvertObjectToTypeMain(Object o, Type type, JavaScriptSerializer serializer, Boolean throwOnError, Object& convertedObject) at System.Web.Script.Services.WebServiceMethodData.StrongTypeParameters(IDictionary`2 rawParams) at System.Web.Script.Services.WebServiceMethodData.CallMethodFromRawParams(Object target, IDictionary`2 parameters) at System.Web.Script.Services.RestHandler.InvokeMethod(HttpContext context, WebServiceMethodData methodData, IDictionary`2 rawParams) at System.Web.Script.Services.RestHandler.ExecuteWebServiceCall(HttpContext context, WebServiceMethodData methodData)"

Any suggestions?

Have a look at the request in Fiddler, and see what's actually going across the wire. It should help you isolate the problem.

Also, have you tried setting a breakpoint in your web method? Does it even make it to that point?