mattoc@tiscali.co.uk wrote:
> Happy new year to all.
>
> I have a strange error that I've been trying for a while now to
> fathom..
>
> Basically I have a hierarchy of state classes that I need to
serialize
> to XML. Some of them can contain Exceptions, so I've decided to
> implement IXmlSerializable to get round the fact that Exception is
not
> serializable.
>
> Here's the implementation code from the (abstract) superclass:
>
> #region IXmlSerializable Members
>
> public void WriteXml(System.Xml.XmlWriter writer)
> {
> writer.WriteAttributeString(XmlNamespaces.XmlSchemaInstance.Prefix,
> "type", XmlNamespaces.XmlSchemaInstance.Uri.ToString(),
> this.GetType().Name);
> WriteAdditionalContentXml(writer);
> }
>
> public System.Xml.Schema.XmlSchema GetSchema()
> {
>
> XmlSchema schema = new XmlSchema();
> schema.Id = this.GetType().FullName;
> schema.TargetNamespace = XmlNamespaces.Service.Uri.ToString();
>
> schema.Namespaces.Add(XmlNamespaces.Service.Prefix,
> XmlNamespaces.Service.Uri.ToString());
> schema.Namespaces.Add(XmlNamespaces.XmlSchemaInstance.Prefix,
> XmlNamespaces.XmlSchemaInstance.Uri.ToString());
>
> XmlSchemaComplexType state = new XmlSchemaComplexType();
> state.Name = this.GetType().Name;
> schema.Items.Add(state);
>
> XmlSchemaSequence sequence = new XmlSchemaSequence();
> sequence.MinOccurs = 0;
> sequence.MaxOccurs = 1;
>
> AddSchemaContent(schema, sequence);
>
> if (sequence.Items.Count > 0)
> {
> state.Particle = sequence;
> }
>
> schema.Compile(new ValidationEventHandler(schemaValidationHandler));
>
> return schema;
> }
>
> public virtual void ReadXml(System.Xml.XmlReader reader)
> {
> }
>
> protected virtual void WriteAdditionalContentXml(XmlWriter writer)
> {
> }
>
> protected virtual void AddSchemaContent(XmlSchema schema,
> XmlSchemaSequence parentSequence)
> {
> }
>
> private void schemaValidationHandler(object sender,
> ValidationEventArgs args)
> {
> Trace.WriteLine(args.Message);
> Debug.Fail(args.Message + ":" + Environment.NewLine +
> Environment.NewLine + args.Exception.ToString() + Environment.NewLine
+
> Environment.NewLine);
> }
>
> #endregion
>
> The problem is this. I can (de)serialize whichever type is specified
as
> the first argument in the XmlSerializer constructor. However,
attempts
> to serialize any types that are specified in the additional types
> argument fail with an InvalidOperationException ("There was an error
> generating the XML document"), the inner exception of which is an
> InvalidCastException ("Specified cast is not valid"), and the stack
> trace of which is:
>
> at System.Xml.Serialization.XmlSerializer.Serialize(XmlWriter
> xmlWriter, Object o, XmlSerializerNamespaces namespaces, String
> encodingStyle)
> at System.Xml.Serialization.XmlSerializer.Serialize(XmlWriter
> xmlWriter, Object o)
> at
>
Limit.Company.LossAdjustment.Tests.State.StatesTest.serialize(FeeState
> state, XmlSerializer serializer) in
>
q:\projects\limit\limit.company.lossadjustment.tests\state\statestest.cs:line
> 131
> at
>
Limit.Company.LossAdjustment.Tests.State.StatesTest.XmlSerializeErrorState()
> in
>
q:\projects\limit\limit.company.lossadjustment.tests\state\statestest.cs:line
> 71
> --InvalidOperationException
> at
>
Microsoft.Xml.Serialization.GeneratedAssembly.XmlSerializationWriter1.Write1_State(Object
> o)
>
> Furthermore, if I explicitly create XML that matches the schema of
one
> of the additional types, it deserializes, but to the type that was
> specified as the FIRST argument of the XmlSerializer constructor. I
> guess this means that I have problems with my schemas somewhere, but
> I'm at a loss as to how to fix them.
>
> Many thanks in advance,
>
> Matt