private void ExecuteContactExchangeCommand(object parameter)
		{
			if (parameter is string == false)
			{
				Console.WriteLine ("Can not exchange contacts. Need user id.");
				return;
			}

			var contactExchange = new ContactExchange () {
				LocalUserId = _profile.Id,
				UserId = parameter as string,
			};

			_repository.SaveContactExchange (contactExchange);
		}
		public void SaveContactExchange (ContactExchange contactExchange)
		{
			throw new NotImplementedException ();
		}