dotnet/wpf · error · XpsSerializationException

SR.XpsSerializerFactory_WriterIsClosed

Error message

SR.XpsSerializerFactory_WriterIsClosed

What it means

XpsSerializerWriter.CheckDisposed throws XpsSerializationException(SR.XpsSerializerFactory_WriterIsClosed) when an operation is attempted after the writer has been closed/finalized (its _xpsDocumentWriter field is nulled by FinalizeWriter). It guards Write, WriteAsync, CancelAsync, and CreateVisualsCollator — using a closed serializer writer is invalid state.

Solutions

1. Do not use the writer after Close/Dispose; create a new XpsSerializerWriter for further writes.
2. Track writer lifetime and null out references once closed.
3. Guard calls with an IsDisposed/IsClosed check before invoking write APIs.

Example fix

// before
writer.Close();
writer.Write(page); // throws
// after
writer.Close();
writer = serializerFactory.CreateXpsSerializerWriter(package);
writer.Write(page);

if (writer == null || writer.IsClosed) throw new InvalidOperationException("writer already closed");

bool CanWrite(XpsSerializerWriter w) => w != null && !w.IsDisposed;

try { writer.Write(page); }
catch (XpsSerializationException ex) when (writerClosed) { /* recreate writer */ }

When it happens

Trigger: Calling Write, WriteAsync, CancelAsync, or CreateVisualsCollator on an XpsSerializerWriter after Close/dispose (FinalizeWriter already ran and set _xpsDocumentWriter to null).

Common situations: Writing additional documents after closing the XPS package; reusing a cached writer that was disposed; CancelAsync racing with Close.

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

• FixedPageReader
• SR.XpsSerializerFactory_WriterIsClosed
• " }} " element found. Expected fixed page element ( }} ).
• ' ' ContentType is not valid.
• ' ' ContentType is not valid.

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/7f8620ab00929381. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/ReachFramework/SerializerFactory/XpsSerializerWriter.cs:473

                FinalizeWriter();
                WritingCompleted.Invoke(sender, e);
            }
        }

        private void xsw_WritingCancelled(object sender, WritingCancelledEventArgs e)
        {
            if ( WritingCancelled != null)
            {
                FinalizeWriter();
                WritingCancelled.Invoke(sender, e);
            }
        }

        private void CheckDisposed()
        {
            if (_xpsDocumentWriter == null)
            {
                throw new XpsSerializationException(SR.XpsSerializerFactory_WriterIsClosed);
            }
        }

        private void FinalizeWriter()
        {
            _xpsDocument.Close();
            _package.Close();
            _xpsDocument = null;
            _xpsDocumentWriter = null;
            _package = null;
        }

        #endregion

        #region Data

        private Package             _package;
        private XpsDocument         _xpsDocument;

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