public List<T> FindVisualChildren<T>(DependencyObject parent) where T : DependencyObject
{
     List<T> childrens = new List<T>();

     this.FindVisualChildrenHelper(parent, childrens);

     return childrens;
}

private void FindVisualChildrenHelper<T>(DependencyObject parent, List<T> childrens) where T : DependencyObject
{
            int count = VisualTreeHelper.GetChildrenCount(parent);

            for (int index = 0; index < count; index++)
            {
                DependencyObject child = VisualTreeHelper.GetChild(parent, index);

                if (child is T typedChild)
                {
                    childrens.Add(typedChild);
                }

                FindVisualChildrenHelper(child, childrens);
        }
}