Problem Model Binding Checkboxes to Object with Dictionary

Question

I've searched SO and couldn't find a specific answer to this problem. I have a model that has a dictionary object called Weekdays and I want to map that to a set of form fields where the key is the day and the value is if it was checked or not.

So the form looks like this:

Monday [ ]
Tuesday [ ]
Wednesday [ ]
Thursday [ ]
Friday [ ]

My model looks like this:

public class Event
{
  [Required(ErrorMessage="All must be checked")]    
  public Dictionary<string,bool> Weekdays { get; set; }
}

Controller:

namespace MvcApplication6.Controllers
{
  public class HomeController : Controller
  {
    public ActionResult Index()
    {
      Event e = new Event();

      e.Name = "awesome";

      e.Weekdays = new Dictionary<string, bool>()
      {
        {"Monday", false },
        {"Tuesday", true },
        {"Wednesday", true },
        {"Thursday", false },
        {"Friday", true },
      };     

      return View("Home", e);
    }


    [HttpPost]
    public ActionResult Index(Event e)
    {        
      var x = e.Weekdays["Monday"];     

      return View("Home", e);
    }

  }
}

My view:

@model MvcApplication6.Models.Event
@{
  Layout = null;
}
<!DOCTYPE html>
<html>
<head>
<style>.formErrors{color:Red}</style>
  <title>Home</title>
</head>
<body>
  <div>
  @using (@Html.BeginForm("Index", "Home")) 
  {     
    // Weekdays   
    foreach (var i in Model.Weekdays)
    {       
      @i.Key @Html.EditorFor(model => model.Weekdays[i.Key]) <br />    
    }     

    <br /><br /><br />

    <input type="submit" value="submit me" />

  }

  </div>
</body>
</html>

Currently, I'm getting a runtime error on the foreach loop, "Object reference not set to an instance of an object."

What's the deal. Thanks. Also, is there a better way to do this altogether?

I guess you're getting this error when you post the form, not before that right? — Jamie Dixon, Jul 25 '11 at 16:14
This answer might provide the info you need: http://stackoverflow.com/questions/962189/how-do-i-bind-a-dictionary-to-a-set-of-checkboxes-using-asp-net-mvc — Jamie Dixon, Jul 25 '11 at 16:24
and this too: http://haacked.com/archive/2008/10/23/model-binding-to-a-list.aspx — Jamie Dixon, Jul 25 '11 at 16:25
In regards to your 1st link, is it possible to do it without utilizing the Form Parameters? I want it to use model binding. For your second link, I've checked it out before, but I cannot get it to apply to what I'm trying to do. Some sample code that applies to my solution would be grateful. Thanks again. — SaltProgrammer, Jul 25 '11 at 17:14

score 1 · Accepted Answer · edited May 23 '17 at 11:47

1

Look at this post ASP.NET MVC Model Binder not working with a dictionary You can also write your own Model Binder for Dictionary, here's an example http://siphon9.net/loune/2010/11/dictionary-model-binder-in-asp-net-mvc2-and-mvc3/

edited May 23 '17 at 11:47

Community

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answered Jul 28 '11 at 16:14

krolik

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Problem Model Binding Checkboxes to Object with Dictionary

1 Answers1