CDavExchangeCalendar::IsExchangeEnabledForUser

static function IsExchangeEnabledForUser($userId)
	{
		if (!self::IsExchangeEnabled())
		{
			return false;
		}

		$exchangeMailbox = COption::GetOptionString("dav", "exchange_mailbox", "");
		$exchangeUseLogin = COption::GetOptionString("dav", "exchange_use_login", "Y");

		$userId = (int)$userId;
		$dbUserList = CUser::GetList(
			"",
			"",
			array("ACTIVE" => "Y", "!UF_DEPARTMENT" => false, "ID_EQUAL_EXACT" => $userId),
			array("SELECT" => array("UF_BXDAVEX_MAILBOX"),
				"FIELDS" => array('ID', 'LOGIN'))
		);
		if ($arUser = $dbUserList->Fetch())
		{
			$mailbox = (($exchangeUseLogin === "Y")
				? $arUser["LOGIN"].$exchangeMailbox
				: $arUser["UF_BXDAVEX_MAILBOX"])
			;
			return (!empty($mailbox));
		}

		return false;
	}