上一篇"
学习.NET(6) ISerializable接口简析"中已经分析过如何把Serializable的对象保存到MemoryStream中。通过BitFormatter可以很轻易的把MemoryStream保存为二进制数组中，无论是存为二进制文件，还是保存在数据库等可以存储数据的地方，以便将来可以轻易的Deserialize。当然二进制数据Byte[]总是不方便使用，可以UnicodeEncoding，BitConverter等辅助类可以很容易的把上述二进制数据转化为String，同样可以进行存储以便将来使用。
然而，除了上述方法之外，还有另外一种选择：保存数据到XML文件。
要指定一个Class可以被存储到XML文件，首先要为该Class应用DataContractAttribute。同时为需要保存的Field应用DataMemberAttribute。特别的是，为了Enum数据，可以应用EnumMemberAttribute属性。
以下为简单的测试代码(根据MSDN的示例代码修改而来)：
[DataContract]
internal enum DisplayLanguage
{
[EnumMember(Value = "EN")]
English = 0,
[EnumMember(Value = "CN")]
Chinese = 1,
}
[DataContract(Name = "Customer", Namespace = "http://www.google.com")]
class TESTData : IExtensibleDataObject
{
private String strFirst = null;
private Int32? nTest = null;
[DataMember()]
public string FirstName
{
get { return strFirst; }
set { strFirst = value; }
}
[DataMember]
public string LastName;
[DataMember()]
public int ID;
[DataMember()]
public DisplayLanguage CellDisplay;
[DataMember()]
public Int32? TestNumber
{
get { return nTest; }
set { nTest = value; }
}
[DataMember()]
public List<String> listValues = new List<string>();
public TESTData(string newfName, string newLName, int newID, DisplayLanguage ds)
{
FirstName = newfName;
LastName = newLName;
ID = newID;
CellDisplay = ds;
nTest = null;
listValues.Add("TEST");
listValues.Add("Test2");
}
private ExtensionDataObject extensionData_Value;
public ExtensionDataObject ExtensionData
{
get
{
return extensionData_Value;
}
set
{
extensionData_Value = value;
}
}
}
以上代码中，我不仅使用了Enum数据，同时使用了Int32?即Nullable<Int32>类型；以及List<String>类型。
以下是测试代码：
public sealed class Test
{
private Test() { }
public static void Main()
{
try
{
WriteObject("DataContractSerializerExample.xml");
ReadObject("DataContractSerializerExample.xml");
}
catch (SerializationException serExc)
{
Console.WriteLine("Serialization Failed");
Console.WriteLine(serExc.Message);
}
catch (Exception exc)
{
Console.WriteLine(
"The serialization operation failed: {0} StackTrace: {1}",
exc.Message, exc.StackTrace);
}
finally
{
Console.WriteLine("Press <Enter> to exit....");
Console.ReadLine();
}
}
public static void WriteObject(string fileName)
{
Console.WriteLine(
"Creating a Person object and serializing it.");
TESTData p1 = new TESTData("Zighetti", "Barbara", 101, DisplayLanguage.Chinese);
p1.FirstName = "Madrid";
p1.TestNumber = 5;
FileStream writer = new FileStream(fileName, FileMode.Create);
DataContractSerializer ser =
new DataContractSerializer(typeof(TESTData));
ser.WriteObject(writer, p1);
writer.Close();
}
public static void ReadObject(string fileName)
{
Console.WriteLine("Deserializing an instance of the object.");
FileStream fs = new FileStream(fileName,
FileMode.Open);
XmlDictionaryReader reader =
XmlDictionaryReader.CreateTextReader(fs, new XmlDictionaryReaderQuotas());
DataContractSerializer ser = new DataContractSerializer(typeof(TESTData));
// Deserialize the data and read it from the instance.
TESTData deserializedPerson =
(TESTData)ser.ReadObject(reader, true);
reader.Close();
fs.Close();
Console.WriteLine(String.Format("{0} {1}, ID: {2}, Display: {3}, Test: {4}",
deserializedPerson.FirstName, deserializedPerson.LastName,
deserializedPerson.ID, deserializedPerson.CellDisplay, deserializedPerson.TestNumber == null? "NULL" : deserializedPerson.TestNumber.Value.ToString()));
}
看看生成的XML文件：
<Customer xmlns="http://www.google.com" xmlns:i="http://www.w3.org/2001/XMLSchema-instance"><CellDisplay>CN</CellDisplay><FirstName>Madrid</FirstName><ID>101</ID><LastName>Barbara</LastName><TestNumber>5</TestNumber><listValues xmlns:a="http://schemas.microsoft.com/2003/10/Serialization/Arrays"><a:string>TEST</a:string><a:string>Test2</a:string></listValues></Customer>
