private void OnContentTextSelectionChanged(
object sender, RoutedEventArgs e)
{
if (_viewModel != null)
{
_viewModel.SelectedText = ContentText.SelectedText;
var selectionStart = ContentText.SelectionStart;
var line = ContentText
.GetLineIndexFromCharacterIndex(selectionStart);
var column = selectionStart -
ContentText.GetCharacterIndexFromLineIndex(line);
_viewModel.CaretLine = line;
_viewModel.CaretColumn = column;
_viewModel.IndexOfCaret = selectionStart;
}
}