Cannot convert null to a value type JSON error


I am getting error 'Cannot convert null to a value type' when trying to deserialize JSON response into class object
I have the following code in C#

var client2 = new RestClient("https://portal.greeneis.com/v4_6_release/apis/3.0/company/contacts/"+CU.BillingContactId);
var request2 = new RestRequest(Method.GET);
request2.RequestFormat = DataFormat.Json;

request2.AddHeader("cache-control", "no-cache");
request2.AddHeader("authorization", "Basic " + token);

IRestResponse response2 = client2.Execute(request2);
JavaScriptSerializer oJS2 = new JavaScriptSerializer();

var oRootObject2 = oJS2.Deserialize<ContactClass.Rootobject>(response2.Content);

With C# class as

public class ContactClass
    {

        public class Rootobject
        {
            public int id { get; set; }
            public string firstName { get; set; }
            public string lastName { get; set; }
            public Type type { get; set; }
            public Company company { get; set; }
            public Site site { get; set; }
            public string addressLine1 { get; set; }
            public string addressLine2 { get; set; }
            public string city { get; set; }
            public string state { get; set; }
            public string zip { get; set; }
            public string country { get; set; }
            public Relationship relationship { get; set; }
            public object department { get; set; }
            public bool inactiveFlag { get; set; }
            public string defaultMergeContactId { get; set; }
            public string securityIdentifier { get; set; }
            public string managerContactId { get; set; }
            public string assistantContactId { get; set; }
            public string title { get; set; }
            public string school { get; set; }
            public string nickName { get; set; }
            public bool marriedFlag { get; set; }
            public bool childrenFlag { get; set; }
            public string significantOther { get; set; }
            public string portalPassword { get; set; }
            public int portalSecurityLevel { get; set; }
            public bool disablePortalLoginFlag { get; set; }
            public bool unsubscribeFlag { get; set; }
            public string gender { get; set; }
            public string birthDay { get; set; }
            public string anniversary { get; set; }
            public string presence { get; set; }
            public string mobileGuid { get; set; }
            public string facebookUrl { get; set; }
            public string twitterUrl { get; set; }
            public string linkedInUrl { get; set; }
            public bool defaultBillingFlag { get; set; }
            public Communicationitem[] communicationItems { get; set; }
            public _Info4 _info { get; set; }
            public string customFields { get; set; }
        }

        public class Type
        {
            public int id { get; set; }
            public string name { get; set; }
            public _Info _info { get; set; }
        }

        public class _Info
        {
            public string type_href { get; set; }
        }

        public class Company
        {
            public int id { get; set; }
            public string identifier { get; set; }
            public string name { get; set; }
            public _Info1 _info { get; set; }
        }

        public class _Info1
        {
            public string company_href { get; set; }
        }

        public class Site
        {
            public int id { get; set; }
            public string name { get; set; }
            public _Info2 _info { get; set; }
        }

        public class _Info2
        {
            public string site_href { get; set; }
        }

        public class Relationship
        {
            public int id { get; set; }
            public string name { get; set; }
            public _Info3 _info { get; set; }
        }

        public class _Info3
        {
            public string relationship_href { get; set; }
        }

        public class _Info4
        {
            public DateTime lastUpdated { get; set; }
            public string updatedBy { get; set; }
            public string communications_href { get; set; }
            public string notes_href { get; set; }
            public string tracks_href { get; set; }
            public string portalSecurity_href { get; set; }
            public string image_href { get; set; }
        }

        public class Communicationitem
        {
            public int id { get; set; }
            public Type1 type { get; set; }
            public string value { get; set; }
            public string extension { get; set; }
            public bool defaultFlag { get; set; }
            public string communicationType { get; set; }
        }

        public class Type1
        {
            public int id { get; set; }
            public string name { get; set; }
            public object _info { get; set; }
        }

    }

var oRootObject2 = oJS2.Deserialize<ContactClass.Rootobject>(response2.Content); line is throwing error that ' Cannot convert null to a value type.'

Lots of solutions online suggesting creating custom Class with nullable types but this won't work for me. I have no control over the Json


Asked by:- pika
1
: 8382 At:- 5/29/2017 3:17:27 PM
C# json Deserialize






2 Answers
profileImage Answered by:- vikas_jk

Thank you for asking a question here.

I had a similar issue in past while working in a project, you can create settings for JavascriptSerializer which ignores Null value's

       var settings = new JsonSerializerSettings
        {
          NullValueHandling = NullValueHandling.Ignore,
          MissingMemberHandling = MissingMemberHandling.Ignore
        };

So your full code can be

           var settings = new JsonSerializerSettings
            {
             NullValueHandling = NullValueHandling.Ignore,
             MissingMemberHandling = MissingMemberHandling.Ignore
            };

           JavaScriptSerializer oJS2 = new JavaScriptSerializer();
           var settings = new JsonSerializerSettings
            {
              NullValueHandling = NullValueHandling.Ignore,
              MissingMemberHandling = MissingMemberHandling.Ignore
            };
            var oRootObject2 = JsonConvert.DeserializeObject<ContactClass.Rootobject>(response2.Content, settings);

That's it, you should not get null value error now, as we will now ignore null values, when Deserliazing JSON into Class.

You can also check article about, how to read JSON into C#(Console application example).

4
At:- 5/29/2017 4:57:28 PM
thanks, good answer, helped me in similar issue 0
By : neena - at :- 9/25/2017 3:29:36 PM


profileImage Answered by:- manish

If your JSON is dynamic as you have mentioned you have no control over JSON, you can deserialize JSON into C# dynamic object like below using using Json.NET

dynamic stuff = JsonConvert.DeserializeObject("{ 'Name': 'John Smith', 'Address': { 'City': 'New York', 'State': 'NY' }, 'Age': 30}");

string name = stuff.Name; // John Smith
string address = stuff.Address.City;// New York

Or Also using Newtonsoft.Json.Linq :

dynamic stuff = JObject.Parse("{ 'Name': 'Jon Smith', 'Address': { 'City': 'New York', 'State': 'NY' }, 'Age': 42 }");

string name = stuff.Name;
string address = stuff.Address.City;

OR check this link https://qawithexperts.com/article/web-api/quick-tip-to-convert-json-into-class-object/26 to quickly convert JSON into class object.

1
At:- 2/16/2018 1:22:25 PM






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