title: Bind RadioGroup inside MvxListView
body: <p>I've got some very tricky problem. I already tried to search the web and even looked into the MvvmCross sources, but I don't seem to be able to figure it out.</p>
  
  <p>I have an MvxListView with a custom Adapter. The reason is, that depending on the "DataContext" of the current ListItem, I want to display some different view.</p>
  
  <p>The list itself represents some sort of questionnaire. So the items in the list are in the form of</p>
  
  <pre><code>new Question("do you need help?"){
      new Answer("yes"),
      new Answer("no"),
      new Answer("maybe")
  }
  </code></pre>
  
  <p>Now the answers shall be shown as a radio button list. 
  So in my custom adapter on "GetChildView", I retrieve the view with the radiogroup and then I 
  "just want to bind that group to my answers" --> so for each answer, there has to be a corresponding radiobutton.</p>
  
  <p>I would love to have the "Answer" object as datacontext for each radiobutton.</p>
  
  <pre><code>radioButton.Bind("Checked", "Chosen"); // where "Chosen" is the boolean property on "Answer"
  </code></pre>
  
  <p>But it would already be fine if the "Question" object could be the datacontext that I bind to</p>
  
  <pre><code>radioGroup.Bind("CheckedRadioButtonId", "ChosenAnswer"); // where "ChosenAnswer" is an int property 
  </code></pre>
  
  <p>on "Question"</p>
  
  <p>So basically I want to bind my radiobutton to the MvxListItem.DataContext in code inside my customadapter.
  But I just cannot figure out how to do that. :/</p>
  
  <p>Can you please give me a hint?</p>
  
  <p>Of course I would love to do the same with a list of checkboxes as soon as multiple answers would be allowed.</p>