Searching for a specific JToken by name in a JObject hierarchy

Question

I have some Json response from server, for example:

{"routes" : [   {      "bounds" : {         "northeast" : {            "lat" : 50.4639653,            "lng" : 30.6325177         },         "southwest" : {            "lat" : 50.4599625,            "lng" : 30.6272425         }      },      "copyrights" : "Map data ©2013 Google",      "legs" : [         {            "distance" : {               "text" : "1.7 km",               "value" : 1729            },            "duration" : {               "text" : "4 mins",               "value" : 223            }, 

And I want to get the value of token 'text' from

      "legs" : [         {            "distance" : {               "text" : "1.7 km",               "value" : 1729            }, 

which is string with value "1.7 km".

Question: is there any build-in function in NewtonsoftJson lib which can be look like:

public string(or JToken) GetJtokenByName(JObject document, string jtokenName) 

or do I need to implement some recursive method which will search JToken by name in all JTokens and JArrays in JObject?

Answer 1

If you are looking for a very specific token and know the path to it, you can navigate to it easily using the built-in SelectToken() method. For example:

string distance = jObject.SelectToken("routes[0].legs[0].distance.text").ToString(); 

If you need to find all occurences of a token with a given name in your JSON, no matter where they occur, then yes you'd need a recursive method. Here is one that might do the trick:

public static class JsonExtensions {     public static List<JToken> FindTokens(this JToken containerToken, string name)     {         List<JToken> matches = new List<JToken>();         FindTokens(containerToken, name, matches);         return matches;     }      private static void FindTokens(JToken containerToken, string name, List<JToken> matches)     {         if (containerToken.Type == JTokenType.Object)         {             foreach (JProperty child in containerToken.Children<JProperty>())             {                 if (child.Name == name)                 {                     matches.Add(child.Value);                 }                 FindTokens(child.Value, name, matches);             }         }         else if (containerToken.Type == JTokenType.Array)         {             foreach (JToken child in containerToken.Children())             {                 FindTokens(child, name, matches);             }         }     } } 

Here is a demo:

class Program {     static void Main(string[] args)     {         string json = @"         {             ""routes"": [                 {                     ""bounds"": {                         ""northeast"": {                             ""lat"": 50.4639653,                             ""lng"": 30.6325177                         },                         ""southwest"": {                             ""lat"": 50.4599625,                             ""lng"": 30.6272425                         }                     },                     ""legs"": [                         {                             ""distance"": {                                 ""text"": ""1.7 km"",                                 ""value"": 1729                             },                             ""duration"": {                                 ""text"": ""4 mins"",                                 ""value"": 223                             }                         },                         {                             ""distance"": {                                 ""text"": ""2.3 km"",                                 ""value"": 2301                             },                             ""duration"": {                                 ""text"": ""5 mins"",                                 ""value"": 305                             }                         }                     ]                 }             ]         }";          JObject jo = JObject.Parse(json);          foreach (JToken token in jo.FindTokens("text"))         {             Console.WriteLine(token.Path + ": " + token.ToString());         }     } } 

Here is the output:

routes[0].legs[0].distance.text: 1.7 km routes[0].legs[0].duration.text: 4 mins routes[0].legs[1].distance.text: 2.3 km routes[0].legs[1].duration.text: 5 mins