Model Binding to IDictionary<int, IList<int>> in ASP.Net MVC 2.0

Question

I'm stuck !!!

Kindly help me out.

I have following view model property in my mvc 2.0 project...

public IDictionary<int, IList<int>> SelectedErrorsErrorType { get; set; }

Basically I have group of checkboxes under one or more tabs. These tabs are like English, German, French etc. etc.. I want to use tabId as dictionary Key and selected checkbox IDs as Dictionary Value (Integer List). I can't seem to bind my model that way. I previously found on stackoverflow that to map to Dictionary Key, we need an hidden field e.g.

<input type="hidden" name="<%: String.Format("SelectedErrorsErrorType[{0}].Key", index) %>"value="<%: item.LanguageId %>" />

That's Fine ! But how do I map Value field against my Key.

Any help would be highly appreciated.

Thanks.

Answer 1

Seems like here is the solution: http://stackoverflow.com/questions/1031416/asp-net-mvc-model-binding-a-set-of-dynamically-generated-checkboxes-how-to

But you can also use

public class ErrorType
{
   public int Key { get; set; }
   public int Value { get; set; }
}

public class ViewModel
{
   public IList<ErrorType> PostedValues { get; set; }

   public IDictionary<int, IList<int>> SelectedErrorsErrorType 
   { 
     get { return PostedValues.GroupBy(x => x.Key).ToDictionary(x => x.Key, x => x.Select(y => y.Value).ToList());
     set { /* backward if you need it */ }
   }
}

and bind to PostedValues.

Answer 2

This was quite easy.. don't know why I couldn't figure this out in the first place.

Here's how it worked for me...

<input type="hidden" name="<%: String.Format("SelectedErrorsErrorType[{0}].Key", index) %>"
                                                            value="<%: item.LanguageId %>" />

<%: Html.CheckBox(String.Format("SelectedErrorsErrorType[{0}].Value[{1}]", index, counter), false, new { @value = errorType.ErrorTypeId })%>