DataContractSerializer.WriteObject Method (XmlWriter, Object)
February 14, 2014
Writes all the object data (starting XML element, content, and closing element) to an XML document or stream with an XmlWriter.
Assembly: System.Runtime.Serialization (in System.Runtime.Serialization.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 written.
The maximum number of objects to serialize has been exceeded. Check the MaxItemsInObjectGraph property.