Symphonary.MenuItemExtensions.OnGroupNameChanged C# (CSharp) Method

        private static void OnGroupNameChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            //Add an entry to the group name collection
            var menuItem = d as MenuItem;

            if (menuItem != null)
            {
                String newGroupName = e.NewValue.ToString();
                String oldGroupName = e.OldValue.ToString();
                if (String.IsNullOrEmpty(newGroupName))
                {
                    //Removing the toggle button from grouping
                    RemoveCheckboxFromGrouping(menuItem);
                }
                else
                {
                    //Switching to a new group
                    if (newGroupName != oldGroupName)
                    {
                        if (!String.IsNullOrEmpty(oldGroupName))
                        {
                            //Remove the old group mapping
                            RemoveCheckboxFromGrouping(menuItem);
                        }
                        ElementToGroupNames.Add(menuItem, e.NewValue.ToString());
                        menuItem.Checked += MenuItemChecked;
                    }
                }
            }
        }