title: How to disable one RadioButton out of three in RadioGroup On my form
body: <p>On my form is have one <code>TRadioGroup</code>. In that <code>TRadioGroup</code>, I add 3 Items. Now I want to disable one item out of three in <code>TRadioGroup</code>.</p>
  
  <p>How do I do this? I write code...</p>
  
  <pre><code>TRadioButton(rgbLoadSurveyTypes.Controls[1]).Enabled := True;
  </code></pre>
  
  <p>...but it gives error "Access Violation". Reason behind this error is </p>
  
  <p><code>rgbLoadSurveyTypes.Controls[1]</code> give <code>null</code> value and<br>
  <code>rgbLoadSurveyTypes</code> show <code>ControlCount = 0</code> and<br>
  <code>Item Count = 3</code></p>