/// <summary>
/// Задание удаления микрорайона
/// </summary>
/// <param name="arg"></param>
/// <returns></returns>
private Task OnDeleteDistrict(OnDelete <District> arg)
{
var item = Districts.FirstOrDefault(s => s.Id == arg.Id);
if (item != null)
{
Districts.Remove(item);
}
return(Task.CompletedTask);
}