dotnet/wpf · error · XpsPackagingException

ReachPackaging_AlreadyHasRootSequenceOrDocument

Error message

ReachPackaging_AlreadyHasRootSequenceOrDocument

What it means

AddFixedDocumentSequence throws this InvalidOperationException when the package already contains a root FixedDocumentSequence (or fixed-document starting part). An XPS package may have only one document sequence root, so adding another is rejected. Check for an existing root sequence before calling.

Solutions

  1. Call AddFixedDocumentSequence only once per package, before the root FixedDocumentSequence is written
  2. Use the existing IXpsFixedDocumentSequenceWriter returned from the first call instead of adding another
  3. Check whether the package already contains a root FixedDocumentSequence before calling
Defensive patterns

Strategy: validation

When it happens

Trigger: Thrown at src/Microsoft.DotNet.Wpf/src/ReachFramework/Packaging/XpsDocument.cs:544 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/6c8fe9df8f038cde. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/ReachFramework/Packaging/XpsDocument.cs:544

        /// is already a starting part causes InvalidOperationException to be
        /// thrown.
        /// </summary>
        /// <returns>Returns a IXpsFixedDocumentSequenceWriter instance.</returns>
        /// <exception cref="SR.ReachPackaging_AlreadyHasRootSequenceOrDocument">Package already has a root DocumentSequence.</exception>
        public
        IXpsFixedDocumentSequenceWriter
        AddFixedDocumentSequence(
            )
        {
            CheckDisposed();
        
            if( CurrentXpsManager == null )
            {
                throw new InvalidOperationException(SR.ReachPackaging_DocumentWasClosed);
            }
            if (_isInDocumentStage)
            {
                throw new XpsPackagingException(SR.ReachPackaging_AlreadyHasRootSequenceOrDocument);
            }
            if ( !CurrentXpsManager.Streaming && null != CurrentXpsManager.StartingPart)
            {
                throw new XpsPackagingException(SR.ReachPackaging_AlreadyHasRootSequenceOrDocument);
            }

            //
            // Create the unique metro part in the package
            //
            PackagePart metroPart = CurrentXpsManager.GenerateUniquePart(XpsS0Markup.DocumentSequenceContentType);

            //
            // Create reader/writer and save a reference to it.
            //
            XpsFixedDocumentSequenceReaderWriter ds = new XpsFixedDocumentSequenceReaderWriter(CurrentXpsManager, this, metroPart);
  
            CurrentXpsManager.StartingPart = ((INode)ds).GetPart();

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