Calling out to you coding genius' out there. I'm blue in the face trying to figure this on out. I'm calling a publicly exposed api to return doctors information (https://npiregistry.cms.hhs.gov/api/?version=2.1&number=1225185168&pretty=on) and I just can't figure out how to reach the lower branches to return back the info I need. It's probably looking square in the eye but I have no idea what I'm missing.

Thanks in advance.

Here's my code (console app in Core 6):

    using System.Net.Http.Headers;

namespace ConsoleProgram
{
    public class NpiRegistryModel
    {
        public string? First_name { get; set; }
        public string? Last_name { get; set; }
        public string? Postal_code { get; set; }
        public string? City { get; set; }
        public int? Number { get; set; }
    }

    public class Program
    {
        private const string URL = "https://npiregistry.cms.hhs.gov/api/";
        private static string urlParameters = "?version=2.1&number=1225185168";

        private static void Main(string[] args)
        {
            HttpClient client = new()
            {
                BaseAddress = new Uri(URL)
            };

            client.DefaultRequestHeaders.Accept.Add(
            new MediaTypeWithQualityHeaderValue("application/json"));

            HttpResponseMessage response = client.GetAsync(urlParameters).Result;
            if (response.IsSuccessStatusCode)
            {
                var dataObjects = response.Content.ReadAsAsync<IEnumerable<NpiRegistryModel>>().Result;
                foreach (var d in dataObjects)
                {
                    Console.WriteLine("Doctor: {0}, {1}", d.Last_name,d.First_name);
                }
            }
            else
            {
                Console.WriteLine("{0} ({1})", (int)response.StatusCode, response.ReasonPhrase);
            }

            client.Dispose();
        }
    }
}

Here's the error I'm getting: System.AggregateException HResult=0x80131500 Message=One or more errors occurred. (Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'System.Collections.Generic.IEnumerable1[ConsoleProgram.NpiRegistryModel]' because the type requires a JSON array (e.g. [1,2,3]) to deserialize correctly. To fix this error either change the JSON to a JSON array (e.g. [1,2,3]) or change the deserialized type so that it is a normal .NET type (e.g. not a primitive type like integer, not a collection type like an array or List<T>) that can be deserialized from a JSON object. JsonObjectAttribute can also be added to the type to force it to deserialize from a JSON object. Path 'result_count', line 1, position 16.) Source=System.Private.CoreLib StackTrace: at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions) at System.Threading.Tasks.Task1.GetResultCore(Boolean waitCompletionNotification) at System.Threading.Tasks.Task`1.get_Result() at ConsoleProgram.Program.Main(String[] args) in C:\Users\j####\source\Prototypes\TestApiCalls\HttpClientDemo\Program.cs:line 32

This exception was originally thrown at this call stack: [External Code]

Inner Exception 1: JsonSerializationException: Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'System.Collections.Generic.IEnumerable`1[ConsoleProgram.NpiRegistryModel]' because the type requires a JSON array (e.g. [1,2,3]) to deserialize correctly. To fix this error either change the JSON to a JSON array (e.g. [1,2,3]) or change the deserialized type so that it is a normal .NET type (e.g. not a primitive type like integer, not a collection type like an array or List) that can be deserialized from a JSON object. JsonObjectAttribute can also be added to the type to force it to deserialize from a JSON object. Path 'result_count', line 1, position 16.

CodePudding user response：

you have to parse your json at first, after this you can extract the data you need

using Newtonsoft.Json;

     var json = response.Content.ReadAsStringAsync().Result;

    var results = JObject.Parse(json)["results"][0];
    NpiRegistryModel npiRegistryModel = results["basic"].ToObject<NpiRegistryModel>();
    npiRegistryModel.PostalCode = (string) results["addresses"][0]["postal_code"];  
    npiRegistryModel.City = (string) results["addresses"][0]["city"];
    npiRegistryModel.Number = (int) results["number"];


public partial class NpiRegistryModel
{
    [JsonProperty("first_name")]
    public string FirstName { get; set; }

    [JsonProperty("last_name")]
    public string LastName { get; set; }

    [JsonProperty("postal_code")]
    public string? PostalCode { get; set; }
    
    [JsonProperty("city")]
    public string? City { get; set; }
    
    [JsonProperty("number")]
    public int? Number { get; set; }

}