title: Bind Xaml Radio button to boolean
body: <p>I saw many posts on how to bind a boolean value to a radio button. But my scenario is that I need to bind it to a radio button and read the selection from the user.</p>
  
  <p>That is no option should be selected intially.</p>
  
  <p>If I bind it to a boolean, since boolean cant be null it shows the default value selected in radio button.</p>
  
  <p>If I use nullable boolean, I still defaults to false when trying to use the converter.</p>
  
  <p>I cant use oneway mode in xaml as I need to check if the radio button selection was made which I do using the bounded variable.</p>
  
  <p>Ant pointers on how to achieve this? </p>