title: Converting API call Json URL string (Json Objects) into C# Datatable (Without using any constructive class with getters and setters or poco)
body: <p>I'm new to Json API call string parsing in C#, I have a requirement where I need to get Json string from a API call and convert that into C# data-table then show the results in a web page using Asp.Net GridView.</p>
  
  <p>I tried several ways. I faced different type of issues in each approach only succeed with my Approach 4(mentioned below). But I don't want to create a separate class (With getter and setters) and converting Json string into object of that class. As I have more than 150 fields for each record in my Json file and also object names are dynamic they are generated randomly. I don't want one to one mapping (Class field to Json field).</p>
  
  <p>Here is my Json file format,</p>
  
  <pre><code>{
  "R_aabdcDgjZwp0ch":{ Record 1 information key value pair } // Here R_aabdcDgjZwp0ch are randomly generated value
  "R_lkYnksdY6qXaPb":{ Record 2 information key value pair } //R_lkYnksdY6qXaPb random
  ………
  "R_7GhjsnB29xWBjp":{ Record n information key value pair }//R_7GhjsnB29xWBjp not fixed value
  }
  </code></pre>
  
  <p>Sample Records from Json string:</p>
  
  <pre><code>{
  "R_3dSKpqkb0JuH0TW":{"ResponseSet":"Default Response Set","Name":"John, Smith","ExternalDataReference":"811221273","EmailAddress":"smithaa@gmail.com","IPAddress":"123.232.12.21","Status":"","StartDate":"2015-07-06 11:10:26","EndDate":"2015-07-06 11:10:55","Finished":"1","RecipientEmail":"smithaa@gmail.com","RecipientLastName":"John","RecipientFirstName":"Smith","MI":"Mia","EntryTerm":"","Classification":"","Type":"","MajorCode":"","Major":"","DeptCode":"","Dept":"","College":"","Age":"","Ethnicity":"","Gender":"","CB1":"","PIDM":"71121027","Military":"","OrientationDate":"4\/7\/2016","H1":1,"H2":1,"H3":2,"H4":2,"H5":"","Q1":"","Q2":"","Q3_1":"","Q3_2":"","Q3_3":"","Q3_4":"","Q3_5":"","Q3_6":"","Q3_7":"","Q3_7_TEXT":"","Q4_1":"","Q4_2":"","Q4_3":"","Q4_4":"","Q4_5":"","Q4_6":"","Q4_7":"","Q4_8":"","Q4_9":"","Q4_10":"","Q4_11":"","Q4_12":"","Q4_12_TEXT":"","Q5":"","Q5_TEXT":"","Q6_1":"","Q6_2":"","Q6_3":"","Q7":"","Q8":"","Q9":"","Q10_1":"","Q10_2":"","Q10_3":"","Q10_4":"","Q11_1":"","Q11_2":"","Q11_3":"","Q11_4":"","Q12_1":"","Q12_2":"","Q12_3":"","Q12_4":"","Q13":"","Q13_TEXT":"","Q14":"","Q14_TEXT":"","Q15_1":"","Q15_2":"","Q15_3":"","Q15_4":"","Q15_5":"","Q15_6":"","Q15_7":"","Q15_8":"","Q16_1":"","Q16_2":"","Q16_3":"","Q16_4":"","Q16_5":"","Q16_6":"","Q16_7":"","Q16_8":"","Q17_1":"","Q17_2":"","Q17_3":"","Q17_4":"","Q17_5":"","Q17_6":"","H6":"","Q18_1":"","Q18_2":"","Q18_3":"","Q19_1":"","Q19_2":"","Q19_3":"","Q19_4":"","Q20":"","Q21_1":"","Q21_2":"","Q22_1":"","Q22_2":"","Q23_1":"","Q23_2":"","Q23_3":"","Q23_4":"","Q24":"","Q24_TEXT":"","Q25":"","Q26":"","Q27":"","Q28":"","H7":"","Q29_1":"","Q29_2":"","Q29_3":"","Q29_4":"","Q29_5":"","Q30":"","Q30_TEXT":"","Q31":"","Q31_TEXT":"","Q32":"","Q33_1":"","Q33_2":"","Q33_3":"","Q33_4":"","Q33_5":"","Q33_6":"","Q33_6_TEXT":"","Q34":"","Q34_TEXT":"","Q35":"","Q35_TEXT":"","Q36_1":"","Q36_2":"","Q36_3":"","Q36_4":"","Q36_5":"","Q36_6":"","Q36_7":"","Q36_7_TEXT":"","Q37":"","H8":1,"H9":1},
  
  "R_1kYrTV300hwdvPP":{"ResponseSet":"Default Response Set","Name":"priya, Sam","ExternalDataReference":"8901212","EmailAddress":"sam12@gmail.com","IPAddress":"123.232.12.21","Status":"","StartDate":"2015-07-06 11:14:18","EndDate":"2015-07-06 11:14:59","Finished":"1","RecipientEmail":"sam@gmail.com","RecipientLastName":"sam","RecipientFirstName":"priya","MI":"","EntryTerm":"","Classification":"","Type":"","MajorCode":"","Major":"","DeptCode":"","Dept":"","College":"","Age":"","Ethnicity":"","Gender":"","CB1":"","PIDM":"71121028","Military":"","OrientationDate":"6\/27\/2016","H1":1,"H2":1,"H3":2,"H4":2,"H5":"","Q1":"","Q2":"","Q3_1":"","Q3_2":"","Q3_3":"","Q3_4":"","Q3_5":"","Q3_6":"","Q3_7":"","Q3_7_TEXT":"","Q4_1":"","Q4_2":"","Q4_3":"","Q4_4":"","Q4_5":"","Q4_6":"","Q4_7":"","Q4_8":"","Q4_9":"","Q4_10":"","Q4_11":"","Q4_12":"","Q4_12_TEXT":"","Q5":"","Q5_TEXT":"","Q6_1":"","Q6_2":"","Q6_3":"","Q7":"","Q8":"","Q9":"","Q10_1":"","Q10_2":"","Q10_3":"","Q10_4":"","Q11_1":"","Q11_2":"","Q11_3":"","Q11_4":"","Q12_1":"","Q12_2":"","Q12_3":"","Q12_4":"","Q13":"","Q13_TEXT":"","Q14":"","Q14_TEXT":"","Q15_1":"","Q15_2":"","Q15_3":"","Q15_4":"","Q15_5":"","Q15_6":"","Q15_7":"","Q15_8":"","Q16_1":"","Q16_2":"","Q16_3":"","Q16_4":"","Q16_5":"","Q16_6":"","Q16_7":"","Q16_8":"","Q17_1":"","Q17_2":"","Q17_3":"","Q17_4":"","Q17_5":"","Q17_6":"","H6":"","Q18_1":"","Q18_2":"","Q18_3":"","Q19_1":"","Q19_2":"","Q19_3":"","Q19_4":"","Q20":"","Q21_1":"","Q21_2":"","Q22_1":"","Q22_2":"","Q23_1":"","Q23_2":"","Q23_3":"","Q23_4":"","Q24":"","Q24_TEXT":"","Q25":"","Q26":"","Q27":"","Q28":"","H7":"","Q29_1":"","Q29_2":"","Q29_3":"","Q29_4":"","Q29_5":"","Q30":"","Q30_TEXT":"","Q31":"","Q31_TEXT":"","Q32":"","Q33_1":"","Q33_2":"","Q33_3":"","Q33_4":"","Q33_5":"","Q33_6":"","Q33_6_TEXT":"","Q34":"","Q34_TEXT":"","Q35":"","Q35_TEXT":"","Q36_1":"","Q36_2":"","Q36_3":"","Q36_4":"","Q36_5":"","Q36_6":"","Q36_7":"","Q36_7_TEXT":"","Q37":"","H8":1,"H9":1}
  }
  </code></pre>
  
  <p>I have tried several ways to parse/consume Json url string to Datatable. I’m receiving below errors.</p>
  
  <p><strong>Approach 1:</strong> Using Json.Net and directly converting from Json string to Data Table using Newtonsoft.Json. JsonConvert.DeserializeObject </p>
  
  <p>Sample Code: </p>
  
  <pre><code>string url ="test.com/json...etc"; //Here actual url to call api
  var json_data = string.Empty;
  // attempt to download JSON data as a string
  json_data = w.DownloadString(url); // we are passing API url here
  DataTable items = JsonConvert.DeserializeObject&lt;DataTable&gt;(json_data); // Exception coming here
  </code></pre>
  
  <p><strong>Exception:</strong> Newtonsoft.Json.JsonSerializationException: Unexpected JSON token when reading DataTable. Expected StartArray, got StartObject. Path '', line 1, position 1.</p>
  
  <p><strong>Approach 2:</strong> I have used <a href="http://json2csharp.com/#" rel="nofollow noreferrer">http://json2csharp.com/#</a> (Which Converts Json input file/Json url into constructive class which will have getters and setters with Root Object to access data from sub classes). But I end up with an exception. However I don't want this approach.</p>
  
  <p><strong>Exception:</strong>   Newtonsoft.Json.JsonSerializationException: Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'System.Collections.Generic.List`1[matrix+RANFpZfdGjZwp0ch]' 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 'R_ANFpZfdGjZwp0ch', line 1, position 21.</p>
  
  <p><strong>Approach 3:</strong> I have tried using below. But ended with an exception.</p>
  
  <pre><code>DataTable dt = (DataTable)JsonConvert.DeserializeObject(json, (typeof(DataTable)));
  </code></pre>
  
  <p><strong>Exception:</strong> Newtonsoft.Json.JsonSerializationException: Unexpected JSON token when reading DataTable. Expected StartArray, got StartObject. Path '', line 1, position 1.
  Tried below to solve this Approach 3 issue. But didn't work.</p>
  
  <ol>
  <li><a href="https://stackoverflow.com/questions/25782765/newtonsoft-json-jsonconvert-to-datatable">Newtonsoft.Json JsonConvert To Datatable</a>  </li>
  <li><a href="http://www.codeproject.com/Questions/817608/Newtonsoft-Json-JsonConvert-To-Datatable" rel="nofollow noreferrer">http://www.codeproject.com/Questions/817608/Newtonsoft-Json-JsonConvert-To-Datatable</a></li>
  <li><a href="https://stackoverflow.com/questions/29562501/converting-json-string-to-datatable">Converting JSON string to DataTable</a></li>
  <li><a href="https://stackoverflow.com/questions/12376474/parsing-with-json-net-unexpected-token-startobject">Parsing with Json.NET: &quot;Unexpected token: StartObject&quot;</a></li>
  </ol>
  
  <p><strong>Approach 4:</strong> With this approach I succeed using constructive class with getters and setters.</p>
  
  <pre><code>string url ="test.com/json...etc"; //Here actual url to call api
  using (var w = new WebClient())
              {
                  var json = string.Empty;
                  // attempt to download JSON data as a string
                  try
                  {
                      json = w.DownloadString(url);
                  }
                  catch (Exception) { }
  
  
                   User obj = new User(json);
  
                  Response.Write(obj.name);
              }
  
  
  public class User
  {
          /********* Used from https://stackoverflow.com/questions/2246694/how-to-convert-json-object-to-custom-c-sharp-object **********/
          public User(string json)
          {
              JObject jObject = JObject.Parse(json);
              JToken jUser = jObject["R_XYZanOp0ch"]; //R_XYZanOp0ch this value is randomly generated. I gave it constant to check for one record. In actual Json file there are so many randomly generated object names exist.
              name = (string)jUser["Name"];
              email = (string)jUser["Email"];
              ExternalDataReference = (string)jUser["NumberReference"];
          }
  
      public string name { get; set; }
      public string ExternalDataReference { get; set; } // student ID
      public string email { get; set; }
  
  
  
  }
  </code></pre>
  
  <p>I got some result using this <strong>Approach 4</strong>. But problem is that we have more than 150 fields and we don't want to make getters and setters for each field and object names are dynamic not fixed. Unfortunately we need all fields data. </p>
  
  <p>Below are my references I used for above approaches.</p>
  
  <ol>
  <li><a href="https://stackoverflow.com/questions/22191167/convert-json-string-to-c-sharp-object-list?noredirect=1&amp;lq=1">Convert Json String to C# Object List</a></li>
  <li><a href="https://stackoverflow.com/questions/11981282/convert-json-to-datatable?noredirect=1&amp;lq=1">Convert JSON to DataTable</a></li>
  <li><a href="https://stackoverflow.com/questions/7641004/how-to-convert-json-into-datatable">How to convert json into datatable?</a></li>
  </ol>
  
  <p>Thanks for reading. Sorry for my long text. Don't consider this post as duplicate, As I tried all ways but still I didn't get desired outcome, hence posting here.
  Can anyone help me or guide me as per my Json string structure, do I need to change any of code? Any samples or reading notes would be helpful.</p>
  
  <p>Thank you.</p>
  
  <p><strong>Update :</strong> I tried both, I got System.FormatException: Input string was not in a correct format exception at array.ToObject(); please let me know If I miss any step in between.</p>
  
  <pre><code>var obj = JObject.Parse(json);
  var array = new JArray(obj.Values());
  //Response.Write("&lt;br/&gt;array[0]" + array[0].ToString()); // I could able to view the record 1 data 
  var dt = array.ToObject&lt;DataTable&gt;(); // Having issue here.
  </code></pre>