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up vote 2 down vote favorite
3

I am using Json.NET in order to parse a json string but when i try to use SelectToken it returns null. Also it seems that Json.NET read the json string as 1 node

here is the JSON

[
   [{
      "input_index":0,
      "candidate_index":0,
      "delivery_line_1":"124 Main St",
      "last_line":"Cambridge MA 02138-5813",
      "delivery_point_barcode":"021385813991",
      "components":{
         "primary_number":"125",
         "street_name":"Main",
         "street_suffix":"St",
         "city_name":"Cambridge",
         "state_abbreviation":"MA",
         "zipcode":"02138",
         "plus4_code":"5813",
         "delivery_point":"99",
         "delivery_point_check_digit":"1"
      },
      "metadata":{
         "record_type":"H",
         "county_fips":"25017",
         "county_name":"New York",
         "carrier_route":"C025",
         "congressional_district":"08",
         "building_default_indicator":"Y"
      },
      "analysis":{
         "dpv_match_code":"D",
         "dpv_footnotes":"AAN1",
         "dpv_cmra":"N",
         "dpv_vacant":"N",
         "ews_match":false,
         "footnotes":"A#H#N#"
      }
   }]
]

and here is the code

JArray o = JArray.Parse(page);
string something = (string)o.SelectToken("county_name");

However it just returns me null and i am totally confused as there is something wrong with JSON.NET parsing this Json string

share|improve this question
    
It's an array... an array doesn't have a county_name... – Jeff Mercado Jul 7 '13 at 19:40
    
it is under metadata – Roman Ratskey Jul 7 '13 at 19:42
    
So how could i retrieve it... – Roman Ratskey Jul 7 '13 at 19:43
    
Also they are double arrays. outer and inner one. – Roman Ratskey Jul 7 '13 at 19:44
up vote 2 down vote accepted

See: What is the JSON.NET equivilant of XML's XPath, SelectNodes, SelectSingleNode?

var data = GetJson();

//You can use the SelectToken to get the value similar to XPath.
var value = JArray.Parse(data)
                  .SelectToken("[0][0].metadata.county_name")
                  .Value<string>();

This can be extended to support multiple elements:

var jArray = JArray.Parse(data);
var countyNames = new List<string>();

foreach(var element in jArray.SelectToken("[0]"))
{
    var value = element.SelectToken("metadata.county_name").Value<string>();

    countyNames.Add(value);
}
share|improve this answer
    
what is the use of [0][0] – Roman Ratskey Jul 7 '13 at 21:12
    
First element of the unnamed outer array and first element of the unnamed inner array. – Romoku Jul 7 '13 at 21:14
    
But i still get null using this code idk why!. i am sorry but could you have a little patience with me to solve this – Roman Ratskey Jul 7 '13 at 21:16
    
Is you are getting null then either the JSON that you are receiving is different, it does not contain the same property, or there is a typo in your code. – Romoku Jul 7 '13 at 21:19
    
i am trying on the same JSON posted... – Roman Ratskey Jul 7 '13 at 21:19
up vote 0 down vote

So, the issue is that you basically have a wrapper around your actual object. You basically have:

Array of objects
  Object
    Metadata
    etc

So basically, get the first JToken out of the JArray and access the metadata from there.

share|improve this answer
1  
Please make you answer richer with a code so another people after me could find it useful – Roman Ratskey Jul 7 '13 at 19:50

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