Windows Phone 7 序列化Serialization: XmlSerializer

转自：http://www.devdiv.com/thread-56865-1-1.html

Currently I am looking for the best solution for object serialization in Windows Phone 7 environment. I will begin my quest with XML Serialization using XmlSerializer Class (popular solution in Silverlight). In this post I will show how to serialize and deserialize objects using XmlSerializer, later I will try to compare several ways of serialization to find out which one is the best.

Additional Information

• XmlSerializer Class
• XML Serialization in the .NET Framework
  

Creating a sample class

I have created special SampleData class to be serialized and deserialized. It is a very simple class containing only two properties and a constructor declaration for filling down both properties (check code bellow). To control XML generation for a class you can use XmlAttribute, XmlElement, etc. Pay attention that only public properties can be serialized. More information about XML-generation can be foundhere andhere (MSDN website).

1. public class SampleData
   
2. {
   
3.     [XmlElement]
   
4.     public string ContentText { get; set; }
   
5. 
   
6.     [XmlElement]
   
7.     public List<int> SomeItems { get; set; }
   
8. 
   
9.     public SampleData()
   
10.     {
    
11.         ContentText = "some text";
    
12.         SomeItems = new List<int>() { 1, 2, 3 };
    
13.     }
    
14. }

Adding a referenceKeep in mind that XmlSerializer requires System.Xml.Serialization namespace to be added to project. To do so right click the project name and choose Add Reference there. Select System.Xml.Serialization namespace on .NET tab (check image bellow).

SerializationBoth serialization and deserialization processes are very easy to implement. For both operations you will need to create an instance of XmlSerializer class and pass it a type of object for serialization. In addition for serialization you will need a stream object to hold serialized object. To serialize an object simply call Serialize method of XmlSerializer instance. I have created the following method for serialization:

1. public static void Serialize(Stream streamObject, object objForSerialization)
   
2. {
   
3.     if (objForSerialization == null || streamObject == null)
   
4.         return;
   
5. 
   
6.     XmlSerializer serializer = new XmlSerializer(objForSerialization.GetType());
   
7.     serializer.Serialize(streamObject, objForSerialization);
   
8. }

Restrictions

• Class for serialization must be public
• Class member for serialization must be public
• Parameterless constructor for a class
  

DeserializationTo deserialize object you will need a stream to read previously serialized data and a type of the object. I have also created a sample method for deserialization (code bellow) that returns deserialized object.

1. public static object Deserialize(Stream streamObject, Type serializedObjectType)
   
2. {
   
3.     if (serializedObjectType == null || streamObject == null)
   
4.         return null;
   
5. 
   
6.     XmlSerializer serializer = new XmlSerializer(serializedObjectType);
   
7.     return serializer.Deserialize(streamObject);
   
8. }

Testing serialization and deserializationI have used the following method to test serialization and deserialization with XmlSerializer. As the result instance of SampleData class after deserialization is exactly the same as the one before the serialization.

1. public static void TestXMLSerialization()
   
2. {
   
3.     // serialization
   
4.     MemoryStream ms = new MemoryStream();
   
5.     XMLSerializerHelper.Serialize(ms, new SampleData());
   
6.     ms.Position = 0;
   
7. 
   
8.     // deserialization
   
9.     var sampleData = XMLSerializerHelper.Deserialize(ms, typeof(SampleData));
   
10. 
    
11.     ms.Close();
    
12. }

Here is how serialized instance of SampleData class looks like:

1. <?xml version="1.0"?>
   
2. <SampleData xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
   
3.   <ContentText>some text</ContentText>
   
4.   <SomeItems>1</SomeItems>
   
5.   <SomeItems>2</SomeItems>
   
6.   <SomeItems>3</SomeItems>
   
7. </SampleData>