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XmlObjectSerializer Class

Provides the base class used to serialize objects as XML streams or documents. This class is abstract.

Namespace:  System.Runtime.Serialization
Assembly:  System.Runtime.Serialization (in System.Runtime.Serialization.dll)

public abstract class XmlObjectSerializer


the type being serialized does not conform to data contract rules. For example, the DataContractAttribute attribute has not been applied to the type.


there is a problem with the instance being serialized.

Extend the XmlObjectSerializer to create your own serializer to serialize and deserialize objects. Both the DataContractSerializer class and the NetDataContractSerializer class inherit from the XmlObjectSerializer and are used to serialize and deserialize objects that conform to data contract rules (objects created using the DataContractAttribute and the DataMemberAttribute).

Notes to Inheritors:

When you inherit from XmlObjectSerializer, you must override the following members: XmlObjectSerializer.WriteStartObject(XmlDictionaryWriter, Object), XmlObjectSerializer.WriteObjectContent(XmlDictionaryWriter, Object), XmlObjectSerializer.WriteEndObject(XmlDictionaryWriter). Additionally, the IsStartObject and ReadObject methods must be implemented for reading and deserializing.

The following example shows a method named WriteObjectWithInstance that includes an XmlObjectSerializer as a parameter. The method serializes an object using either the DataContractSerializer or NetDataContractSerializer by calling the WriteObject method.

public class Test
    private void WriteObjectWithInstance(XmlObjectSerializer xm, Company graph,
       string fileName)
        // Use either the XmlDataContractSerializer or NetDataContractSerializer, 
        // or any other class that inherits from XmlObjectSerializer to write with.
        FileStream fs = new FileStream(fileName, FileMode.Create);
        XmlDictionaryWriter writer = XmlDictionaryWriter.CreateTextWriter(fs);
        xm.WriteObject(writer, graph);
        Console.WriteLine("Done writing {0}", fileName);

    private void Run()
        // Create the object to write to a file.
        Company graph = new Company();
        graph.Name = "";

        // Create a DataContractSerializer and a NetDataContractSerializer. 
        // Pass either one to the WriteObjectWithInstance method.
        DataContractSerializer dcs = new DataContractSerializer(typeof(Company));
        NetDataContractSerializer ndcs = new NetDataContractSerializer();
        WriteObjectWithInstance(dcs, graph, @"datacontract.xml");
        WriteObjectWithInstance(ndcs, graph, @"netDatacontract.xml");

    public class Company
        public string Name;

    static void Main()
            Test t = new Test();

        catch (InvalidDataContractException iExc)
            Console.WriteLine("You have an invalid data contract: ");

        catch (SerializationException serExc)
            Console.WriteLine("There is a problem with the instance:");

        catch (QuotaExceededException qExc)
            Console.WriteLine("The quota has been exceeded");
        catch (Exception exc)

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0

.NET Compact Framework

Supported in: 3.5