CODEWITHSUNDEEP
c#linqjson.net
Nani
Nani

Reputation: 1176

Cannot access child value on Newtonsoft.Json.Linq.JProperty -Error happens while checking JObject using LinQ

I have a JObject object which has Json data. I need to collect all KeyValuePairs of whichever has "state": true. Before I read the value, I want to make sure that the JObject has at least one KeyValuePairs with JToken (Value) has "state": true.
Below is my JSON:

{  
  "AAA": {
    "state": false,
    "version": "1.1.14202.0",
    "result": null,
    "update": "20171018"
  },
  "BBB": {
    "state": true,
    "version": "3.10.1.18987",
    "result": null,
    "update": "20171018"
  },
  "CCC": {
    "state": true,
    "version": "1.1.1.2",
    "result": null,
    "update": "20171018"
  }
}

And the below is the code currently I'm checking with, which is throwing an exception saying Cannot access child value on Newtonsoft.Json.Linq.JProperty:

JObject jsonData = //JSON data;
List<JToken> tokens = jsonData .Children().ToList();
if (tokens.Any(each => each["state"].ToString().ToLower().Contains("true")))
{
  List<JToken> tokensWithStateTrue = tokens.Where(each => each["state"].ToString().ToLower().Contains("true")).ToList();
}

Please help me and correct the LinQ statement to read only JTokens with state as true.

Upvotes: 4

Views: 45983

Answers (1)

ismael.
ismael.

Reputation: 438

This worked for me, looks like you're missing an extra call to Children() to access the properties you need. 

//parse JSON and grab it's children. 
var jsonData = JObject.Parse(json).Children();

List<JToken> tokens = jsonData .Children().ToList();

or

List<JToken> tokens = jsonData .Children().Children().ToList();
if (tokens.Any(each => each["state"].ToString().ToLower().Contains("true")))
{
    List<JToken> tokensWithStateTrue = tokens.Where(each => each["state"].ToString().ToLower().Contains("true")).ToList();
}

enter image description here

Alternatively you could do this. The code below will return a dictionary with only your states with true values. Otherwise, it will return an empty dictionary if you have no true values. 

var dictionaryTokensWithTrueValues = jsonData.Children()
.Select(u => u as JProperty)
.Where(v => v.Value["state"].ToString().ToLower().Contains("true"))
.ToDictionary(k => k.Name, v => v.Value);

//check if you have any true values
if (dictionaryTokensWithTrueValues.Count() > 0)
{
     //do something with true states here
     var accessBBB = dictionaryTokensWithTrueValues["BBB"]; //{{"state": true,"version": "3.10.1.18987","result": null,"update": "20171018"}}
}
else
{ 
     //no true states. Do something else
}

Upvotes: 9

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