var addr = await GetIdentityServerAddress();

        var result = "";
        TokenResponse token = null;
        TokenClient client;

        if (loginType == LoginType.UsernamePassword)
            client = new TokenClient(addr, ClientTypes.UsernamePassword, "xt");
        else if (loginType == LoginType.WindowsAccountUsernamePassword ||
            loginType == LoginType.WindowsAccountCurrent)
            client = new TokenClient(addr, ClientTypes.Windows, "x");
        else if (loginType == LoginType.SmartCard)
            client = new TokenClient(addr, ClientTypes.Siths, "x", new HttpMessageHandler);
        else
            throw new Exception("Login " + loginType.ToTranslatedString() + " is not implemented");

        token = await client.RequestResourceOwnerPasswordAsync(username, password);