WPFcheckbox: add click event additionaly to checked/unchecked

In WPF, I want to open a dialog the fist time the user clicks on a CheckBox - some kind of warning, if he really wants to enable this option. The event will be handled in code-behind.

Something like this could be possible:

<CheckBox IsChecked="{Binding Path=Something.Enabled}"
          PreviewMouseDown="CheckBox_PreviewMouseDown"/>
<!-- or: -->
<CheckBox IsChecked="{Binding Path=Something.Enabled}"
          Click="CheckBox_Click"/>

I additionally want to bind the CheckBox checked and unchecked event to the IsChecked property like in the example above.