I am getting an error when trying to XML serialize an object

Question

System.Web.Services.Protocols.SoapException: Server was unable to process request. ---> System.InvalidOperationException: There was an error generating the XML document. ---> System.InvalidOperationException: The type ProfileChulbul was not expected. Use the XmlInclude or SoapInclude attribute to specify types that are not known statically.
   at System.Xml.Serialization.XmlSerializationWriter.WriteTypedPrimitive(String name, String ns, Object o, Boolean xsiType)
   at Microsoft.Xml.Serialization.GeneratedAssembly.XmlSerializationWriterProfileDefinitionExportHolder.Write1_Object(String n, String ns, Object o, Boolean isNullable, Boolean needType)

if you see ' ProfileChulbul ' is an object, I am trying to serialize

Answer 1

This happens when the type you're serializing has a property of a type that is not statically known to the serializer instance. For example, if the type ProfileChulbul has a base type, which is how it is referenced from what you're serializing, the serializer won't know how to work with it.

You have a couple options for resolving this problem:

• Add the [XmlInclude(typeof(ProfileChulbul))] attribute (and additional attributes for any other types that will be used) to ProfileChulbul 's base class

• Modify the class you use for serialization to use generics instead of Object

• Pass typeof(ProfileChulbul) (and any other types that will be used) into the serializer constructor at runtime, like so:

  var knownTypes = new Type[] { typeof(ProfileChulbul), typeof(ProfileSomethingElse) };

  var serializer = new XmlSerializer(typeof(TheSerializableType), knownTypes);

Answer 2

Based on the part of the stacktrace "Use the XmlInclude or SoapInclude attribute to specify types that are not known statically", I would bet you are trying to serialize an interface or collection of interfaces? Xml Serialization does not allow this, try marking the interface with the XmlInclude attributes.