WPF - Stop radio button click with message box

Question

I have a set of dynamically generated radio buttons that when clicked, fill a large amount of textboxes with data. They are bound to a property on the view model that pulls data from a service based on the radio button's label text.

What I want to do is to show a MessageBox when the radio button is clicked, so if the user accidentally (or intentionally) clicks another radio button, I can confirm that's what they wanted to do.

I can catch the click event and display a MessageBox, but the underlying property is changed anyway, triggering the data change. Is there a way that I can stop execution while the MessageBox is shown? Is the Click event the wrong event to use? I'm pretty new to WPF.

Radio button click event:

private void RadioButton_Click(object sender, RoutedEventArgs e)
{
  var radioButton = sender as RadioButton;
  MessageBoxResult result = MessageBox.Show("Choosing this sample will override any changes you've made. Continue?", "Confirmation", MessageBoxButton.YesNo, MessageBoxImage.Question);
  if (result == MessageBoxResult.Yes)
  {
    radioButton.IsChecked = true;
    return;
  }
}

After the second line of the method and before the user's choice is returned is when the property is updated anyway.

Answer 1

Click event is raised after RadioButton is already checked but you can use PreviewMouseLeftButtonDown event instead and set Handled to true

<RadioButton ... PreviewMouseLeftButtonDown="RadioButton_PreviewMouseLeftButtonDown"/>

and in code

private void RadioButton_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
    e.Handled = true;
    var radioButton = sender as RadioButton;
    MessageBoxResult result = MessageBox.Show("Choosing this sample will override any changes you've made. Continue?", "Confirmation", MessageBoxButton.YesNo, MessageBoxImage.Question);
    if (result == MessageBoxResult.Yes)
    {
        radioButton.IsChecked = true;
    }
}