不是所有的代码路径返回值？

Question

我对这部分代码感到困惑。你能帮助我吗？

static public async Task<Artikelen> getItems (string f = "")
    {
        await EnsureAccess();
        string filter = "&$filter=substringof('" + f + "',Code)+eq+true";
        string orderby = "&$orderby=Code+asc";
        Uri request = new Uri(Gegevens.BASE_URI + "/api/v1/" + CurrentDivision + "/logistics/Items?access_token=" + AccessToken + filter + orderby);

        HttpClient client = new HttpClient();
        client.DefaultRequestHeaders.Accept.Clear();
        client.DefaultRequestHeaders.Accept.Add(new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/json"));
        //  client.DefaultRequestHeaders.Accept.Add(new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/multipart/form-data"));
        client.DefaultRequestHeaders.Accept.Add(new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/x-www-form-urlencoded"));
        HttpResponseMessage respons = await client.GetAsync(request);
        if (respons.IsSuccessStatusCode == false)
        {
            //await errorAlert("getSalesItemPrices Mislukt:  status = " + respons.StatusCode.ToString());
            return null;
        }
        respons.EnsureSuccessStatusCode();
        string responsecontent = await respons.Content.ReadAsStringAsync();

        //JArray results = JObject.Parse(responsecontent).GetValue("d")["results"].First.ToObject<JArray>();
        JArray results = JObject.Parse(responsecontent).GetValue("d")["results"].ToObject<JArray>();
    }

错误发生在JArray结果

中

JObject.Parse(responsecontent).GetValue("d")["results"].ToObject<JArray>();

我认为应该返回一个值或什么？