Define the User type to deserialize the JSON into.

public class User
{
    public bool IsMember { get; set; }
    public string Name { get; set; }
    public int Age { get; set; }
}

There is no need to mark a type or the members of that type with special attributes to opt into the deserialization – all public members are included automatically in the data contract. This is a simplification of the data contract programming model, which had required an explicit DataMemberAttribute attribute for each member and a DataContractAttribute for each type to be included in the data contract. The current programming model enables a member’s name and visibility to determine whether it is serialized. For more information, see Silverlight Serialization.

The following code shows how to create an instance of the DataContractJsonSerializer and use it to deserialize a responseStream into a User object.

DataContractJsonSerializer serializer = 
    new DataContractJsonSerializer(typeof(User));
User user = (User)serializer.ReadObject(responseStream);

bool isMember = user.IsMember;
string name = user.Name;
int age = user.Age;

Silverlight provides the JsonPrimitive, JsonArray, and JsonObject types, which allow you to treat JSON in a weakly-typed manner. This approach allows you to dynamically access the values of primitive JSON types (string, number, Boolean) and index into structured JSON types (object and array), without having to pre-define types (such as the User type) to deserialize into. The following code shows an example of how this can be done.

JsonObject user = (JsonObject)JsonObject.Load(responseStream);
bool isMember = user["IsMember"];
string name = user["Name"];
int age = user["Age"];

Using JsonObject and with LINQ allows us to easily deal with complex JSON objects. Assume, for example, that the following JSON is contained in the responseStream object of type Stream.

[{"IsMember" : true, "Name" : "John", "Age" : 24}, 
{"IsMember" : false, "Name" : "Paul", "Age" : 44},
{"IsMember" : true, "Name" : "George", "Age" : 12}]

To retrieve all people who are members, use the following LINQ query over a JsonArray object.

JsonArray users = (JsonArray)JsonArray.Load(responseStream);

var members = from member in users
              where member["IsMember"]
              select member;

foreach (JsonObject member in members)
{
   string name = member["Name"];
   int age = member["Age"];

   // Do something...

}

Other Resources