public async Task Init()
        {
            var list = await _vrstaclanka.Get <List <VrstaClanka> >(null);

            VrstaClankaList.Clear();
            foreach (var z in list)
            {
                VrstaClankaList.Add(z);
            }
        }
        public async Task PretragaClanaka()
        {
            if (VrstaClankaList.Count() == 0)
            {
                var vrstaclankalist = await _vrstaclanka.Get <List <VrstaClanka> >(null);

                foreach (var i in vrstaclankalist)
                {
                    VrstaClankaList.Add(i);
                }
            }
            if (SelectedVrstaClanka != null)
            {
                ClanakSearchRequest request = new ClanakSearchRequest();
                request.VrstaClankaId = SelectedVrstaClanka.VrstaClankaId;
                var list = await _clanak.Get <List <Clanak> >(request);

                ClanakList.Clear();
                foreach (var b in list)
                {
                    ClanakList.Add(b);
                }
            }
        }