Question

After I upgraded to the beta, I’m having trouble with Html.RadioButtonList. Can someone show me what I’m doing wrong?

The code:

<% Html.RadioButtonList(     'voter' + voter.Id,     new SelectList(new[]{'yes','no','abstain'}, 'yes')).Each(x => Response.Write(x)); %> 

And the exception I get:

[ArgumentNullException: Value cannot be null. Parameter name: value]    System.Web.Mvc.Html.InputExtensions.RadioButton(HtmlHelper htmlHelper, String name, Object value, Boolean isChecked, IDictionary`2 htmlAttributes) +214    Microsoft.Web.Mvc.<>c__DisplayClass1.<RadioButtonListInternal>b__0(ListItem item) in c:\dd\Cicero\src\Mvc\main\src\MvcFutures\Mvc\RadioExtensions.cs:86    System.Linq.WhereSelectListIterator`2.MoveNext() +107    System.Linq.Buffer`1..ctor(IEnumerable`1 source) +259    System.Linq.Enumerable.ToArray(IEnumerable`1 source) +81    Microsoft.Web.Mvc.RadioListExtensions.RadioButtonListInternal(HtmlHelper htmlHelper, String name, SelectList selectList, Boolean usedViewData, IDictionary`2 htmlAttributes) in c:\dd\Cicero\src\Mvc\main\src\MvcFutures\Mvc\RadioExtensions.cs:88    Microsoft.Web.Mvc.RadioListExtensions.RadioButtonList(HtmlHelper htmlHelper, String name, SelectList selectList) in c:\dd\Cicero\src\Mvc\main\src\MvcFutures\Mvc\RadioExtensions.cs:29 

Many thanks in advance!
Rob

Answer 1

It looks like you may have found a bug in the MVC framework. The other overloads of RadioButtonList seem to work just fine, but that particular overload barfs.

From looking at Reflector (and using the stack trace) I looks like things go awry at this line:

    return selectList.GetListItems().Select<ListItem, string>(delegate (ListItem item) {     return htmlHelper.RadioButton(name, item.Value, item.Selected, htmlAttributes); }).ToArray<string>(); 

In the Microsoft.Web.Mvc.RadioListExtensions.RadioButtonListInternal method. I assume this code worked fine in Preview 5?