XmlObjectSerializer.WriteStartObject Method (XmlWriter, Object)
Writes the start of the object's data as an opening XML element using the specified XmlWriter.
Assemblies: System.Runtime.Serialization (in System.Runtime.Serialization.dll)
System.Runtime.Serialization.Xml (in System.Runtime.Serialization.Xml.dll)
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.
the maximum number of objects to serialize has been exceeded. Check the MaxItemsInObjectGraph property.