Question

I would like to pass parameters to my webservice from jquerys ajax. How can I do that?

I’ve already looked through a few of the related questions but couldn’t find a solution that worked for me. I’ve tried this: jQuery AJAX parameter not being passed to MVC but I’m not using mvc so I’m sure that is why the solution isn’t working.
My jquery looks like this:

            $.ajax({
                type: "POST",
                contentType: "application/json; charset=utf-8",
                url: "CarService.svc/GetCar",
                data: {CarID:117},
                dataType: "json",
                success: function (data) {
                    $("#lblCurrentTime").text("");
                    $("#lblCurrentTime").text(data.d.CarID);
                }
            });

Something is wrong with my ‘data’ part, correct? If leave the data: part as data: “{}” I can get my method to run (and I don’t pass any parameter) but the moment I try the above out firebug tells me:

Firebug's log limit has been reached. 0 entries not shown.  Preferences  
POST http://localhost:64461/TimeService.svc/GetCar
POST http://localhost:64461/TimeService.svc/GetCar

500 Internal Server Error
  1.12s

My Webservice looks like this:

[OperationContract]
    public CarTable GetCar(int id)
    {
        using (var sqlc = new SqlConnection(@"sdfgsdfg"))
        {
            sqlc.Open();
            var cmd = sqlc.CreateCommand();
            cmd.CommandText = "HUGE QUERY HERE ^^";
            //id = 117;
            cmd.Parameters.Add("CarID", System.Data.SqlDbType.Int).Value = id;
            using (var reader = cmd.ExecuteReader())
            {
                CarTable Cars = new CarTable();

                while (reader.Read())
                {
                    Cars.CarID = reader["CarID"].ToString();
                    Cars.CarName = reader["CarName"].ToString();
                }


                return Cars;

            }
        }
    }
[DataContract]
public class CarTable
{
    [DataMember]
    public string CarID { get; set; }
    [DataMember]
    public string CarName { get; set; }
}

EDIT: If I change the data part to:

data: CarID=117,

I get Sys.ParameterCountException: Parameter count mismatch.
[Break On This Error] {name: “format”, type: String}

Answer 1

First you should verify that you include attribute

[WebInvoke (ResponseFormat = WebMessageFormat.Json)]

to the GetCar method or do the same in web.config.

Second you should use data:"117" or data:JSON.stringify(117) instead of data: {feat:117}.

UPDATED: If you would has a more complex data input, for example as an object CarTable the data parameter should be data:JSON.stringify({CarID: 117, CarName: "BMW"}), so it should be built in the same way. The JSON.stringify is defined in http://www.json.org/js.html.

One more remark. After the successful return of data you will see that the data returned back should be accessed not with data.d.CarID, but with data.CarID instead. ASMX web-service place the data in the property d, but not WCF service.

UPDATED 2: I don’t know which small error you do, so I created a small WCF service which do what you need. You can download the source code here http://www.ok-soft-gmbh.com/jQuery/WcfData.zip. To be sure that you will be able compile it I used Visual Studio 2008. In Visual Studio 2010 the web.config file can be much more simple.