MVC C# opslaan naar json file

  public class HomeController : Controller
    {
        // GET: Home
   
        public ActionResult Index()
        {
            //   jsonkalender.Add(new kalender() { Password = "" });
            //kalender kl = new kalender();
            //kl.Password = obj.Password;
            //kl.MyEnum = TestEnum.taak;
            //obj.Password = kl.Password;
            //Load(null);

           
                return View();
        }

     


        private const string JsonFileName1 = @"C:\\Users\Alexander\Desktop\times1.json";
        private List<kalender> _times;


       
        
        [HttpPost]
        public ActionResult Index(kalender obj)
        {
          //  Load(obj);
          //  _times.Add(new kalender() { Datum = DateTime.Now.ToString() });
            kalender kl = new kalender();
           Json(new { datum = obj.Datum,wachtwoord = obj.Password });
           // _times.Add(obj);
            
            try
            {
           
            }
            catch (Exception) { }
           
            obj.SelectedEnumId++;
         
          //  kl.Password = obj.Password;
            var json = JsonConvert.SerializeObject(obj, Formatting.Indented);
         
            
            using (var writer = new StreamWriter(JsonFileName1))
            {
                writer.Write(json);
                
            }
            return View();
        }
    
       

       

        private void Load(kalender obj)
        {

            if (System.IO.File.Exists(JsonFileName1))
            {
                using (var reader = new StreamReader(JsonFileName1))
                {
                    var json = reader.ReadToEnd();
                    obj = JsonConvert.DeserializeObject<kalender>(json);

                }
            }

            if (obj == null)
                obj = new kalender();
        }

    




    }
    
}

@model PE1.Models.kalender
@{
    ViewBag.Title = "Index";
    <script src="//ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
    <link rel="stylesheet" href="//ajax.googleapis.com/ajax/libs/jqueryui/1.11.1/themes/smoothness/jquery-ui.css" />
    <script src="//ajax.googleapis.com/ajax/libs/jqueryui/1.11.1/jquery-ui.min.js"></script>
}


@{
    AjaxOptions options = new AjaxOptions();
    options.HttpMethod = "POST";
    options.Confirm = "Zeker?";
    options.OnBegin = "OnBegin";
    options.OnComplete = "OnComplete";
    options.OnFailure = "OnFailure";
    options.OnSuccess = "OnSuccess";
    options.LoadingElementId = "divProgress";
    options.LoadingElementDuration = 1000;
    options.UpdateTargetId = "divResponse";
    options.InsertionMode = InsertionMode.InsertAfter;
    
}





<script type="text/javascript">
    $(function () { // will trigger when the document is ready
        $('.datepicker').datepicker(); //Initialise any date pickers
        
    });
</script>


    <div>
       <h1>Online Kalender</h1> 
        <div id="kader">
      <p>THuis</p>
@using (Html.BeginForm("Index", "Home", options))
{
    @Html.ValidationSummary(true)
    
    <fieldset>
        <legend>Kaldender</legend>
        @*@Html.DropDownListFor(model => model.Password, listItems)*@<br />
        @Html.LabelFor(model => model.Password)<br />

        @Html.EditorFor(model => model.Password)
       
        @Html.ValidationMessageFor(model => model.Password)<br />
        @Html.EnumDropDownListFor(model => model.MyEnum)

        <div class="form-group input-group-sm">
            @Html.LabelFor(model => model.Datum)
            @Html.TextBoxFor(model => model.Datum, new { @class = "form-control datepicker", placeholder = "Enter Drop-off date here..." })
            @Html.ValidationMessageFor(model => model.Datum)
        </div>
        <input type="submit" value="Submit"/>
        <input type="reset" value="Reset"/>
     
       
        
    </fieldset>
    @Ajax.ActionLink("Klik hier om een Ajax ActionLink uit te voeren", "ProcessLink", options)



}

 public class kalender
    {
        //public string Datum { get; set; }
       //  [Required]  
      //  [DataType(DataType.Date)]
      //  public Nullable<System.DateTime> Datum { get; set; }

     public string Datum { get; set; }

        [Required]    
        public string Password { get; set; }
              [Required]  
        public string Type { get; set; }
              [Required]
     [Key]

        public int SelectedEnumId { get; set; }
              [Required]  
        public TestEnum MyEnum { get; set; }


    }
}

Alvast bedankt