Convert JSON object to C# model Web API 2

Question

This is my 4th production level system using AngularJS and web API 2 C# backend. I am not coming to this with no experience BUT....I just cannot get the very simple conversion working. I normally use complex models between the Angular UI and Web API 2 backend without issue so very frustrated as this is so simple.

I am posting the JSON below:

{
"appSelection": [
  {
  "name": "Withdrawal Service",
  "selected": true
  }
],
"dateSelection": {
  "startDate": "2016-06-13T23:00:00.000Z",
  "endDate": "2016-07-27T07:52:03.510Z"
},
"eventTypes": [
  {
  "name": "Fail",
  "selected": true
  },
  {
  "name": "Success",
  "selected": true
  }
]
}

To a Web API controller: (edited for brevity)

        [HttpPost]
        [Route("search")]
        [ResponseType(typeof(ProcessLog[]))]
        public async Task<IHttpActionResult> getLogs(LogRequest request)
        {
            string requestBody = string.Empty;
            using (var stream = new MemoryStream())
            {
                var context = (HttpContextBase)Request.Properties["MS_HttpContext"];
                context.Request.InputStream.Seek(0, SeekOrigin.Begin);
                context.Request.InputStream.CopyTo(stream);
                requestBody = Encoding.UTF8.GetString(stream.ToArray());
            }

Which accepts this model:

public class LogRequest
        {
            public DateViewModel DateSelection { get; set; }
            public NameAndSelect[] appSelection { get; set; }
            public NameAndSelect[] eventTypes { get; set; }
        }

        public class NameAndSelect
        {
            public bool selected { get; set; }
            public string name { get; set; }
        }
        public class DateViewModel
        {
            public DateTime startDate { get; set; }
            public DateTime endDate { get; set; }
        }

The output from the requestBody is

{"appSelection":[{"name":"Withdrawal Service","selected":true}],"dateSelection":{"startDate":"2016-06-13T23:00:00.000Z","endDate":"2016-07-27T07:52:03.510Z"},"eventTypes":[{"name":"Fail","selected":true},{"name":"Success","selected":true}]}

Which shows that the JSON is being correctly POST'ed to the web API controller but the auto model binding is failing. The request object (web api receiving model) is

DateSelection : null
appselection : null
eventTypes : null

I just cannot see why and where. Been trying this for > 2 days! would really appreciate a fresh pair of eyes.

Thanks in advance

Update #1:

Changed model to the below with still failing auto binding

public class LogRequest
        {
            public DateViewModel DateSelection { get; set; }
            public List<NameAndSelect> appSelection { get; set; }
            public List<NameAndSelect> eventTypes { get; set; }
        }

Update #2:

I have tried simplifying the model to

public class LogRequestViewModel
    {
        public string testString { get; set; }
        public DateTime startDate { get; set; }
        public DateTime endDate { get; set; }
        public DateSelection dateselection { get; set; }
     }
public class DateSelection
     {
        public string startDate { get; set; }
        public string endDate { get; set; }
     }

and posting:

{"teststring":"plap","startdate":"2016-07-27T09:28:38.404Z","enddate":"2016-07-27T09:28:38.404Z","dateselection"
:{"startdate":"2016-07-27T09:28:38.404Z","enddate":"2016-07-27T09:28:38.404Z"}}

I receive:

dateselection:null
enddate:      {27/07/2016 10:28:38}
startdate:    {27/07/2016 10:28:38}
teststring:   "plap"

Which suggests it is able to convert the datetime without issue but deeper objects are causing problems

I just tried to reproduce the error, and everything worked perfectly. I created an ApiController with a model just like yours and then posted with PostMan. — smoksnes
– smoksnes, Commented Jul 27, 2016 at 8:18
I just tried with JQuery.ajax request and it works.. Edit: Oh, a bit slow.. Nvm.. — Hyperdingo
– Hyperdingo, Commented Jul 27, 2016 at 8:22
@MadEddie, is it a blank project? If not, try to remove everything that might mess up the model binding. Formatters in config, modelbinders etc. As this works in a blank project I would assume that you got something behind the curtains that disrupts the model binding. Try remove everything piece by piece. — smoksnes
– smoksnes, Commented Jul 27, 2016 at 8:34

Mad Eddie · Accepted Answer · 2016-07-27 10:08:44Z

3

Thanks to @Smoksnes I commented out all JSON formatters which are in the startup classes and classes in App_Start. Unfortunately this did not resolve the problem. When run-commenting all the commented out lines I found the below in my WebApiConfig.cs

var jsonFormatter = config.Formatters.OfType<JsonMediaTypeFormatter>().First();
            jsonFormatter.SerializerSettings.ContractResolver = new CamelCasePropertyNamesContractResolver();
            jsonFormatter.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Serialize;
            jsonFormatter.SerializerSettings.PreserveReferencesHandling = Newtonsoft.Json.PreserveReferencesHandling.None;
            jsonFormatter.SerializerSettings.MaxDepth = 1;

The bottom line! Doh. Commenting ALL JSON formatters hadn't fixed it but re-enabling them all APART from this line fixed it. I guess I needed the combination of some of the other formatters but not MaxDepth one.

Thanks All

answered Jul 27, 2016 at 10:08

Mad Eddie

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2 Comments

smoksnes Over a year ago

The real question is; why was it there in the first place? And what breaks now when you removed it... :)

Mad Eddie Over a year ago

@smoksnes It was an attempt to stop Entity Framework from returning JSON containing entities which are deeply related/linked (see mass recursion) within my model. I now add ProxyCreationEnabled everytime I init my entity model :(

Pankaj Gupta · Accepted Answer · 2016-07-27 09:24:37Z

0

    public class AppSelection
{
    public string name { get; set; }
    public bool selected { get; set; }
}

public class DateSelection
{
    public string startDate { get; set; }
    public string endDate { get; set; }
}

public class EventType
{
    public string name { get; set; }
    public bool selected { get; set; }
}

public class RootObject
{
    public List<AppSelection> appSelection { get; set; }
    public DateSelection dateSelection { get; set; }
    public List<EventType> eventTypes { get; set; }
}
change this model to your model and then try hope it will useful for you

answered Jul 27, 2016 at 9:24

Pankaj Gupta

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5 Comments

Mad Eddie Over a year ago

Same empty model I'm afraid

Pankaj Gupta Over a year ago

strange, are ou able to store this json o not.

Pankaj Gupta Over a year ago

@MadEddie why you using memory stream , curious to know

Mad Eddie Over a year ago

It is because the HTTPOST content can only be read once and the inbuilt model binding of web API reads it before this method

Pankaj Gupta Over a year ago

show the full code it's difficult to identify the error

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