void ShowTreeView()
{
var list = EnumHelper.ConvertEnumToList <int>(typeof(UserType));
//var list = dc.system_user.GroupBy(x => x.user_type).ToList();
foreach (var item in list)
{
NodeData n = new NodeData();
n.Name = item.Description; //device_id
n.Id = item.Value; //device_id
roots.Add(n);
}
treeView1.ItemsSource = roots;
}