How do I debug “cannot convert to system.collections.generic.list” error

Question

var httpClient = new HttpClient();
        var response = await httpClient.GetStringAsync("http://192.168.1.57/smsapi/api/kullanici/" + viewModel.Item.ID);
        var GrupKullanicilarList = JsonConvert.DeserializeObject<Kullanicilarr>(response);
       ---> string TelefonNoList = GetTelno(GrupKullanicilarList);


public string GetTelno(List<Kullanicilarr> GrupKullanicilarList)
    {
        List<string> TelefonNoList = new List<string>();
        foreach (Kullanicilarr Kullanici in GrupKullanicilarList)
        {
            TelefonNoList.Add("<TelefonNo><TelNo>" + Kullanici.Telefonno.ToString() + "</TelNo></TelefonNo>");
        }

        return string.Join("\n", TelefonNoList);

It gaves an error on the Fourth line in the beginning where I put arrow:"cannot convert from 'SmsApp.Models.Kullanicilarr' to 'System.Collections.Generic.List' How should I write the last line?

Answer 1

In line 3,

 var GrupKullanicilarList = JsonConvert.DeserializeObject<Kullanicilarr>(response);

you are deserializing the http Response as Kullanicilarr object.

and you are passing the Kullanicilarr to GetTelno(List<Kullanicilarr> GrupKullanicilarList) which expects List of Kullanicilarr. That's why you are getting this error.

Can you check if the http response is returning List<Kullanicilarr> ? If yes then you need to change line 3 as,

 var GrupKullanicilarList = JsonConvert.DeserializeObject<List<Kullanicilarr>>(response);

If not, then you need to change the method GetTelno param as GetTelno(Kullanicilarr GrupKullanicilarList) and update its functionality since you will be getting single object instead of an array