Applied XML Programming for Microsoft .NET.pdf - Csbdu.in

string soapText = Encoding.UTF8.GetString(buf);The MemoryStream object reads data only as bytes. Especially in a strong-typedenvironment like the .NET Framework, an array of bytes and a string are as different asapples and oranges. Fortunately, the encoding classes provide for handy conversionmethods. The Encoding static class belongs to the System.Text namespace.Deserializing ObjectsTo rebuild a living instance of a previously serialized object, you call the Deserializemethod on the specified formatter. The deserializer returns an object that you cast tothe particular class type you need, as shown here:StreamReader reader = new StreamReader(filename);Employee emp1 = (Employee) soap.Deserialize(reader.BaseStream);reader.Close();The .NET Framework serialization mechanism also allows you to control the postdeserializationprocessing and explicitly handle data being serialized and deserialized.In this way, you are given a chance to restore transient state and data that, for onereason or another, you decide not to serialize. Remember that by marking a field withthe [NonSerializable]attribute, you keep it out of the serialized stream.By implementing the IDeserializationCallback interface, a class indicates that it wants tobe notified when the deserialization of the entire object is complete. The class caneasily complete the operation by re-creating parts of the state and adding anyinformation not made serializable. The OnDeserialization method is called after the typehas been deserialized.Finally, it goes without saying that you can't serialize to, say, SOAP, and then pretendto deserialize using the binary formatter. See the section "Further Reading," on page518, for more information about run-time binary and SOAP serialization.From SOAP to XML SerializationA second, very special type of .NET Framework serialization is XML serialization.Compared to ordinary .NET Framework object serialization, XML serialization is sodifferent that it shouldn't even be considered another type of formatter. It is similar toSOAP and binary formatters because it also persists and restores the object's state, butwhen you examine the way each serializer works, you see many significant differences.XML serialization is handled by using the XmlSerializer class, which also enables youto control how objects are encoded into elements of an XML schema. In addition todifferences in goals and implementation details, the strongest difference between runtimeand XML serialization is in the level of type fidelity they provide.Run-time object serialization guarantees full type fidelity. For this reason, binary andSOAP serialization are particularly well-suited to preserving the state of an objectacross multiple invocations of an application. For example, .NET Framework remoting(see Chapter 12) uses run-time serialization to marshal objects by value from oneAppDomain to another. Whereas run-time serialization is specifically aimed atserializing object instances, XML serialization is a system-provided (as opposed toobject-provided) mechanism for serializing the data stored in an object instance into awell-formed schema.The primary goal of XML serialization is making another application, possibly anapplication running on a different platform, effectively able to consume any stored data.Let's recap the key differences between run-time and XML serialization:• Persisted properties Run-time serialization takes into account anyproperties, regardless of the scope a property has in the context of theclass. XML serialization, on the other hand, avoids private, protected, and391