Read and parse a Json File in C

Question

I have spent the best part of two days  faffing  about with code samples and etc   trying to read a very large JSON file into an array in c  so I can later split it up into a 2d array for processing   The problem I was having was I could not find any examples of people doing what I was trying to do  This meant I was just editing code a little an hoping for the best   I have managed to get something working that will    Read the file Miss out headers and only read values into array  Place a certain amount of values on each line of an array   So I could later split it an put into 2d array    This was done with the code below but it crashes the program after entering a few lines into the array  This might have to do with the file size      If the file extension was a jave file the following     load method will be use else it will move on to the     next else if statement if  fileExtension      json          int count   0      int count2   0      int inOrOut   0      int nRecords 1       JsonTextReader reader   new JsonTextReader new StreamReader txtLoaction Text        string   rawData   new string 5       while  reader Read                  if  reader Value    null              if  inOrOut    1                                if  count    6                                        nRecords                        Array Resize ref rawData  nRecords                         textBox1 Text      r n                       count   0                                    rawData count2     reader Value             r n                  inOrOut   0                  count                    if  count2    500                                        MessageBox Show rawData 499                                                else                               inOrOut   1                           A snippet of the JSON I am working with is             millis    1000           stamp    1273010254           datetime    2010 5 4 21 57 34           light    333           temp    78 32           vcc    3 54           I need the values out of this JSON   For example  I need  3 54   but I would not want it to print the  vcc    I am hoping someone can show me how to read a JSON file in and only extract the data that I need and put it into an array or something that I can use to later put into an array

User · Answer

string jsonFilePath     quot C  MyFolder myFile json quot                string json   File ReadAllText jsonFilePath   Dictionary lt string  object gt  json Dictionary    new JavaScriptSerializer    Deserialize lt Dictionary lt string  object gt  gt  json    foreach  var item in json Dictionary           parse here

User · Answer

This can also be done in the following way   JObject data   JObject Parse File ReadAllText MyFilePath

User · Answer

For finding the right path I m using      var pathToJson   Path Combine  my   path   config   default Business Area json       var r   new StreamReader pathToJson      var myJson   r ReadToEnd           my path config default Business Area json           do parsing here       Path Combine uses the Path PathSeparator and it checks whether the first path has already a separator at the end so it will not duplicate the separators  Additionally  it checks whether the path elements to combine have invalid chars    See https   stackoverflow com a 32071002 4420355

User · Answer

Based on  L B  s solution  the  typed as Object rather than Anonymous  VB code is  Dim oJson As Object   JsonConvert DeserializeObject File ReadAllText MyFilePath     I should mention that this is quick and useful for constructing HTTP call content where the type isn t required  And using Object rather than Anonymous means you can maintain Option Strict On in your Visual Studio environment - I hate turning that off

User · Answer

Doing this yourself is an awful idea   Use Json NET   It has already solved the problem better than most programmers could if they were given months on end to work on it   As for your specific needs  parsing into arrays and such  check the documentation  particularly on JsonTextReader   Basically  Json NET handles JSON arrays natively and will parse them into strings  ints  or whatever the type happens to be without prompting from you   Here is a direct link to the basic code usages for both the reader and the writer  so you can have that open in a spare window while you re learning to work with this   This is for the best  Be lazy this time and use a library so you solve this common problem forever

User · Answer

This code can help you  string  filePath   Path GetDirectoryName System AppDomain CurrentDomain BaseDirectory    JObject data   JObject Parse  filePath

User · Answer

How about making everything easier with Json NET      public void LoadJson                 using  StreamReader r   new StreamReader  quot file json quot                          string json   r ReadToEnd                List lt Item gt  items   JsonConvert DeserializeObject lt List lt Item gt  gt  json                        public class Item               public int millis          public string stamp          public DateTime datetime          public string light          public float temp          public float vcc         You can even get the values dynamically without declaring Item class      dynamic array   JsonConvert DeserializeObject json       foreach var item in array                Console WriteLine  quot  0   1  quot   item temp  item vcc

User · Answer

For any of the JSON parse  use the website http   json2csharp com   easiest way  to convert your JSON into C  class to deserialize your JSON into C  object     public class JSONClass            public string name   get  set            public string url   get  set            public bool visibility   get  set            public string idField   get  set            public bool defaultEvents   get  set            public string type   get  set                 Then use the JavaScriptSerializer  from System Web Script Serialization   in case you don t want any third party DLL like newtonsoft   using  StreamReader r   new StreamReader  jsonfile json         string json   r ReadToEnd       JavaScriptSerializer jss   new JavaScriptSerializer       var Items   jss Deserialize lt JSONClass gt  json       Then you can get your object with Items name or Items Url etc

[c#] Read and parse a Json File in C#

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