dotnet/wpf · error · XpsSerializationException

SR.ReachSerialization_FixedDocumentInDocument

Error message

SR.ReachSerialization_FixedDocumentInDocument

What it means

RegisterDocumentStart rejects starting a FixedDocument while another document is still open (_documentStartState true). XPS forbids nested FixedDocuments, so a second RegisterDocumentStart without RegisterDocumentEnd throws XpsSerializationException(SR.ReachSerialization_FixedDocumentInDocument).

Solutions

  1. Call RegisterDocumentEnd before starting the next document.
  2. Pair every RegisterDocumentStart with exactly one RegisterDocumentEnd in the writer loop.
  3. Reinitialize the serialization manager if a previous error left the document state machine inconsistent.

Example fix

// before
manager.RegisterDocumentStart();
manager.RegisterDocumentStart(); // throws
// after
manager.RegisterDocumentStart();
// ...serialize document...
manager.RegisterDocumentEnd();
manager.RegisterDocumentStart();
Defensive patterns

Strategy: validation

Validate before calling

bool docOpen = _docStarted && !_docEnded;
if (docOpen) throw new InvalidOperationException("Previous FixedDocument was not ended.");

Try / catch

try { manager.RegisterDocumentStart(); }
catch (XpsSerializationException ex) when (ex.Message.Contains("FixedDocumentInDocument")) { manager.RegisterDocumentEnd(); manager.RegisterDocumentStart(); }

Prevention

When it happens

Trigger: Calling RegisterDocumentStart twice without an intervening RegisterDocumentEnd, i.e. nesting a FixedDocument inside an open FixedDocument.

Common situations: Custom writers that miss the end-of-document call between documents; re-entrant or event-driven serialization; recovery paths that left _documentStartState set after an exception.

Understand the failure class

Background: "Invalid state transition" errors: "status must be X, actually Y", "already rejected/charging/uninstalled", "cannot ... while running" — what they mean when a library rejects your call — this error's family across 31 libraries.

Related errors

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/754f650281b7e04e. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/ReachFramework/Serialization/manager/XpsOMSerializationManager.cs:700

        RegisterDocumentSequenceEnd()
        {
            //
            // It is invalid to have a document sequence with no fixed documents
            // If no fixed documents have been searialzed throw
            //
            if (_documentNumber <= 0)
            {
                throw new XpsSerializationException(SR.ReachSerialization_NoFixedDocuments);
            }
        }

        internal
        void
        RegisterDocumentStart()
        {
            if( _documentStartState )
            {
                throw new XpsSerializationException(SR.ReachSerialization_FixedDocumentInDocument);
            }
            if( _pageStartState)
            {
                throw new XpsSerializationException(SR.ReachSerialization_FixedDocumentInPage);
            }
            //
            // Entering Document  Started state
            //
            _documentStartState = true;
            //
            // Increment the number of documents serialized
            //
            _documentNumber += 1;
            //
            // Clearing the number of pages for this document
            //
            _pageNumber = 0;
        }

View on GitHub (pinned to 81131a70a4)