Using JsonConvert DeserializeObject to deserialize Json to a C POCO class

Question

Here is my simple User POCO class        lt summary gt      The User class represents a Coderwall User       lt  summary gt  public class User            lt summary gt          A User s username  eg   sergiotapia  mrkibbles  matumbo           lt  summary gt      public string Username   get  set              lt summary gt          A User s name  eg   Sergio Tapia  John Cosack  Lucy McMillan           lt  summary gt      public string Name   get  set              lt summary gt          A User s location  eh   Bolivia  USA  France  Italy           lt  summary gt      public string Location   get  set         public int Endorsements   get  set      Todo      public string Team   get  set      Todo            lt summary gt          A collection of the User s linked accounts           lt  summary gt      public List lt Account gt  Accounts   get  set              lt summary gt          A collection of the User s awarded badges           lt  summary gt      public List lt Badge gt  Badges   get  set         And the method I m using to deserialize a JSON response into a User object  this actual JSON call is here    private User LoadUserFromJson string response        var outObject   JsonConvert DeserializeObject lt User gt  response       return outObject      This fires an exception      Cannot deserialize the current JSON object  e g    name   value      into type    System Collections Generic List 1 CoderwallDotNet Api Models Account     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  accounts github   line 1    position 129    Having never worked with this DeserializeObject method before  I m kind of stuck here   I ve made sure that the property names in the POCO class are the same as the names in the JSON response    What can I try to deserialize JSON into this POCO class

User · Answer

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.`

The whole message indicates that it is possible to serialize to a List object, but the input must be a JSON list. This means that your JSON must contain

"accounts" : [{<AccountObjectData}, {<AccountObjectData>}...],

Where AccountObject data is JSON representing your Account object or your Badge object

What it seems to be getting currently is

"accounts":{"github":"sergiotapia"}

Where accounts is a JSON object (denoted by curly braces), not an array of JSON objects (arrays are denoted by brackets), which is what you want. Try

"accounts" : [{"github":"sergiotapia"}]

User · Answer

Another  and more streamlined  approach to deserializing a camel-cased JSON string to a pascal-cased POCO object is to use the CamelCasePropertyNamesContractResolver    It s part of the Newtonsoft Json Serialization namespace  This approach assumes that the only difference between the JSON object and the POCO lies in the casing of the property names  If the property names are spelled differently  then you ll need to resort to using JsonProperty attributes to map property names   using Newtonsoft Json   using Newtonsoft Json Serialization          private User LoadUserFromJson string response         JsonSerializerSettings serSettings   new JsonSerializerSettings        serSettings ContractResolver   new CamelCasePropertyNamesContractResolver        User outObject   JsonConvert DeserializeObject lt User gt  jsonValue  serSettings        return outObject

User · Answer

Along the lines of the accepted answer  if you have a JSON text sample you can plug it in to this converter  select your options and generate the C  code   If you don t know the type at runtime  this topic looks like it would fit   dynamically deserialize json into any object passed in  c

User · Answer

You could create a JsonConverter   See here for an example thats similar to your question

User · Answer

That s not exactly what I had in mind    What do you do if you have a generic type to only be known at runtime   public MyDTO toObject       try       var methodInfo   MethodBase GetCurrentMethod        if  methodInfo DeclaringType    null          var fullName   methodInfo DeclaringType FullName         this dtoName        Type type   Type GetType fullName         if  type    null            var obj   JsonConvert DeserializeObject payload           var obj   JsonConvert DeserializeObject lt type MemberType GetType   gt  payload        lt --- type                                           Example for java     Convert this to C      return JSONUtil fromJSON payload  Class forName dtoName  false  getClass   getClassLoader          catch  Exception ex        throw new ReflectInsightException MethodBase GetCurrentMethod   Name  ex

User · Answer

The accounts property is defined like this    accounts    github   sergiotapia     Your POCO states this   public List lt Account gt  Accounts   get  set      Try using this Json    accounts     github   sergiotapia      An array of items  which is going to be mapped to the list  is always enclosed in square brackets   Edit  The Account Poco will be something like this   class Account       public string github   get  set        and maybe other properties   Edit 2  To not have an array use the property as follows   public Account Accounts   get  set      with something like the sample class I ve posted in the first edit

User · Answer

Here is a working example    Keypoints are    Declaration of Accounts Use of JsonProperty attribute      using  WebClient wc   new WebClient          var json   wc DownloadString  http   coderwall com mdeiters json        var user   JsonConvert DeserializeObject lt User gt  json       -  public class User            lt summary gt          A User s username  eg   sergiotapia  mrkibbles  matumbo           lt  summary gt       JsonProperty  username        public string Username   get  set              lt summary gt          A User s name  eg   Sergio Tapia  John Cosack  Lucy McMillan           lt  summary gt       JsonProperty  name        public string Name   get  set              lt summary gt          A User s location  eh   Bolivia  USA  France  Italy           lt  summary gt       JsonProperty  location        public string Location   get  set          JsonProperty  endorsements        public int Endorsements   get  set      Todo        JsonProperty  team        public string Team   get  set      Todo            lt summary gt          A collection of the User s linked accounts           lt  summary gt       JsonProperty  accounts        public Account Accounts   get  set              lt summary gt          A collection of the User s awarded badges           lt  summary gt       JsonProperty  badges        public List lt Badge gt  Badges   get  set       public class Account       public string github     public class Badge        JsonProperty  name        public string Name       JsonProperty  description        public string Description       JsonProperty  created        public string Created       JsonProperty  badge        public string BadgeUrl

[c#] Using JsonConvert.DeserializeObject to deserialize Json to a C# POCO class

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