WebAPI post action complex type Parameter doesn't invoke custom MediaTypeFormatter and remains null

Question

I am trying to post the data from jquery to ASP.Net WebAPI post method in order to save it.

here is my jquery method that sends the request

'saveAbsenceRecord': function (absenceRecord) {
        var url = helper.apiPath + 'absence';
        $.ajax({
            url: url,
            type: 'POST',
            data: JSON.stringify(absenceRecord) ,
            contentType: 'application/json; charset=utf-8',
            async: false,
            success: function (data) {
                return data;
            },
            error: function (x, y, z) {
                alert(x + '\n' + y + '\n' + z);
            }
        });
};

Below is my json as captured from request

"{\"AbsenceDate\":\"11 March 2014\",\"IsHalfDay\":false,\"DateModified\":\"18 March 2014\",\"User\":{\"Id\":2,\"Name\":\"\",\"EmpId\":\"\",\"LanId\":\"\",\"EmailId\":\"\",\"Permissions\":[]},\"ModifiedBy\":{\"Id\":2,\"Name\":\"\",\"EmpId\":\"\",\"LanId\":\"\",\"EmailId\":\"\",\"Permissions\":[]},\"Type\":{\"Id\":4,\"Reason\":\"Unplanned\"},\"Description\":\"Test\"}"

Here is my WebAPI post method

// POST api/absence
        public HttpResponseMessage Post([FromBody]AbsenceRecord absenceRecord)
        {
            try
            {
                if (ModelState.IsValid)
                {
                    Store store = new Store();
                    var result = store.UpdateAbsenceRecord(absenceRecord);
                    return Request.CreateResponse(HttpStatusCode.OK, result);
                }
                else
                {
                    return Request.CreateResponse(HttpStatusCode.InternalServerError, "Invalid model state");
                }
            }
            catch (Exception ex)
            {
                return Request.CreateResponse(HttpStatusCode.InternalServerError, ex.Message);
            }
        }

Here is how my parameter type

 public class User : IEntity
    {
        public int Id { get; set; }
        [MaxLength(10)]
        public string EmpId { get; set; }
        [MaxLength(50)]
        public string UserName { get; set; }
        public virtual List<UserPermission> Permissions { get; set; }
        public string EmailId { get; set; }
        public string LanId { get; set; }
    }
public class AbsenceType : IEntity
    {
        public int Id { get; set; }
        [MaxLength(50)]
        public string Reason { get; set; }
        [MaxLength(10)]
        public string ColorHash { get; set; }
    }
    public class AbsenceRecord : IEntity
    {
        public int Id { get; set; }
        public DateTime AbsenceDate { get; set; }
        public virtual AbsenceType Type { get; set; }
        public bool IsHalfDay { get; set; }
        public DateTime DateModified { get; set; }
        public string Description { get; set; }
        public virtual User User { get; set; }
        public virtual User ModifiedBy { get; set; }
    } 

I have a doubt that my Json isn't matching to the structure of the parameter type. So I would need eiter model binder or MediaType Formatter. Since I want to send the data in body I would not opt for Binder.

I have tried writting media type formatter and registered it as

public class AbsenceRecordFormatter : MediaTypeFormatter
    {
        public AbsenceRecordFormatter()
        {
            SupportedMediaTypes.Add(new MediaTypeHeaderValue("application/json"));   
        }
        public override bool CanReadType(Type type)
        {
            return type == typeof(AbsenceRecord);
        }
        public override bool CanWriteType(Type type)
        {
            return type == typeof(AbsenceRecord);
        }

        public override System.Threading.Tasks.Task WriteToStreamAsync(Type type, object value, System.IO.Stream writeStream, System.Net.Http.HttpContent content, System.Net.TransportContext transportContext)
        {                
            return base.WriteToStreamAsync(type, value, writeStream, content, transportContext);
        }
    }


config.Formatters.Add(new AbsenceRecordFormatter());

but that code isn't invoked when this method is called. Can any body suggested why formatter is not being invoked please?

Answer 1

The global configuration.Formatters collection is evaluated in order. Therefore the default JSON formatter will be selected before your formatter. Either remove the JSON one from the formatter collection or insert your formatter at the beginning.

 config.Formatters.Insert(0,new AbsenceRecordFormatter());