static void OnShowLineNumbersChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
TextEditor editor = (TextEditor)d;
var leftMargins = editor.TextArea.LeftMargins;
if ((bool)e.NewValue) {
LineNumberMargin lineNumbers = new LineNumberMargin();
Line line = (Line)DottedLineMargin.Create();
leftMargins.Insert(0, lineNumbers);
leftMargins.Insert(1, line);
var lineNumbersForeground = new Binding("LineNumbersForeground") { Source = editor };
line.SetBinding(Line.StrokeProperty, lineNumbersForeground);
lineNumbers.SetBinding(Control.ForegroundProperty, lineNumbersForeground);
} else {
for (int i = 0; i < leftMargins.Count; i++) {
if (leftMargins[i] is LineNumberMargin) {
leftMargins.RemoveAt(i);
if (i < leftMargins.Count && DottedLineMargin.IsDottedLineMargin(leftMargins[i])) {
leftMargins.RemoveAt(i);
}
break;
}
}
}
}
