What's the difference between DataContractJsonSerializer and JavaScriptSerializer?

Question

The .NET Framework ships with System.Runtime.Serialization.Json.DataContractJsonSerializer and System.Web.Script.Serialization.JavaScriptSerializer, both of which de/seriali

Answer 1

Both do approximately the same but using very different infrastructure thus applying different restrictions on the classes you want to serialize/deserialize and providing different degree of flexibility in tuning the serialization/deserialization process.

For DataContractJsonSerializer you must mark all classes you want to serialize using DataContract atrtibute and all members using DataMember attribute. As well as if some of you classes have enum members, then the enums also must be marked as DataContract and each enum member - with EnumMember attribute. Also DataContractJsonSerializer allows you fine control over the whole process of serialization/deserialization by altering types resolution logic and replacing the types you serialize with surrogates.

For JavaScriptSerializer you must provide parameterless constructor if you plan on deserializing objects from json string.

For me, I usually use JavaScriptSerializer in presentation logic, where there's a simple model I want to render in Json together with page, without additional ajax requests. And I even usually don't have to deserialize them back to c# - so there's no overhead at all. But if it's persistence logic, where I want to save objects into a data store (usually no-sql storage), to load them later, I prefer using DataContractJsonSerializer because the overhead of putting attributes is worth of flexibility in the serialization/deserialization process tuning, especially when it comes to loading of serialized data into the objects of the newer version, with updated definitions