jQuery ajax在响应中返回null

Question

I would like retrieve data from ma Web Service method but it returns null.

I test with a method (GetTEST() in my Web Service) that return a string and it works well.

When I'm testing with WCFTestClient.exe, Statistic_1 method works well, but with JQuery it returns null.

Here is JavaScript code :

function getStatistic1() {

var response;
var allstat1 = [];

$.ajax({
    type: 'GET',
    url: 'http://localhost:52768/Service1/Statistic_1',
    contentType: 'application/json; charset=utf-8',
    dataType: 'json',
    success: function (msg) {
        response = msg.Items;
        console.log(msg);

        for (var i = 0; i < response.length; i++) {
            allstat1[i] = [response[i].Geografisch_zone];
        }
        fillDataTable(allstat1);
    },
    error: function (e) {
        alert("error loading statistic 1");
    }
});
}

Here is my IService1.cs

[DataContractFormatAttribute]
[ServiceContract(Namespace ="WSSage100")]
public interface IService1
{

    [OperationContract]
    [WebInvoke(Method = "GET",ResponseFormat = WebMessageFormat.Json)]
    string GetTEST();

    [OperationContract]
    [WebInvoke(Method = "GET", ResponseFormat = WebMessageFormat.Json)]
    ResponseStatistic_1 Statistic_1();
}

Here is Service1.svc

[AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]
public class Service1 : IService1
{

    public string GetTEST()
    {
        return "OKKKKKKKK";
    }

    public ResponseStatistic_1 Statistic_1()
    {...}
}

Here is "console.log(msg)" displays : Object {ErrorMessage: "Object reference not set to an instance of an object.", ErrorOccured: true, Items: null, NbRecord: 0}

ResponseSatistic_1 class :

public class ResponseStatistic_1 : IBaseClientEntity
{
    public ResponseStatistic_1()
    {

    }

    public ResponseStatistic_1(Statistic_1 [] items) : this()
    {
        this.Items = items;
    }

    #region Properties
    public Statistic_1[] Items
    {
        get;
        set;
    }
}

And Statistic_1 class :

public class Statistic_1
{
    private string _geografisch_zone;
    private decimal[] _sum; 
    private int _yearStart;
    private int _yearEnd;

    ...
}

Answer 1

您将返回字符串"OKKKKKK"但已在$.ajax函数中将dataType设置为JSON，因此必须取消设置dataType或返回诸如"{response: 'OKKKK'}" 。

Answer 2

Please change response = msg.Items; to response = msg;

also the @campsjos answer was said that.

Answer 3

I solved the problem.

I had 2 projects in my solution, the WCF and an application console that will do to turn back the web service.

I also added the connectionstrings in app.config of the GettingStartedHost project and now it works well.