dotnet/wpf · error · FileFormatException

SR.XpsValidatingLoaderPrintTicketHasIncorrectType

Error message

SR.XpsValidatingLoaderPrintTicketHasIncorrectType

What it means

The target part of a PrintTicket relationship must have Content Type application/vnd.ms-printing.printticket+xml. When ValidateRelationships resolves the relationship target and its type/subtype doesn't match, it throws FileFormatException because the referenced part is not a real PrintTicket.

Solutions

Ensure the PrintTicket relationship target part has Content Type application/vnd.ms-printing.printticket+xml (fix [Content_Types].xml or override entry).
Point the relationship at the actual PrintTicket part instead of the wrong target.
Replace the target with a genuine PrintTicket (serialize a PrintTicket/PrintQueue ticket to a properly typed part).
Validate all printticket rels with a quick pass over GetRelationshipsByType before loading.

Example fix

// before
PackagePart ticket = pkg.CreatePart(ticketUri, "application/xml");
// after
PackagePart ticket = pkg.CreatePart(ticketUri, "application/vnd.ms-printing.printticket+xml");

Defensive patterns

Strategy: validation

Validate before calling

const string printTicketType = "application/vnd.ms-printing.printticket+xml";
foreach (var rel in fixedPart.GetRelationshipsByType(printTicketRel)) {
    var target = package.GetPart(PackUriHelper.ResolvePartUri(fixedPart.Uri, rel.TargetUri));
    if (!target.ContentType.Equals(printTicketType, StringComparison.OrdinalIgnoreCase))
        throw new InvalidDataException($"PrintTicket rel target {target.Uri} has wrong type {target.ContentType}");
}

Type guard

static bool IsPrintTicketPart(PackagePart p) =>
    p.ContentType.Equals("application/vnd.ms-printing.printticket+xml", StringComparison.OrdinalIgnoreCase);

Try / catch

try { loader.Load(packageStream); }
catch (FileFormatException ex) { // wrong ticket target type: fix [Content_Types].xml or retarget rel, then retry
    FixPrintTicketContentTypes(packageStream); loader.Load(packageStream); }

Prevention

Create PrintTicket parts with the exact vnd.ms-printing.printticket+xml content type.
Add a PrintTicket MIME default/override in [Content_Types].xml.
After retargeting relationships, re-verify target part types.

When it happens

Trigger: Loading an XPS package where a PrintTicket relationship points to a part whose Content Type is not application/vnd.ms-printing.printticket+xml (e.g. points to an XML settings file, an image, or a part with a typo'd MIME type in [Content_Types].xml).

Common situations: Relationship targets edited or re-pointed by tooling without updating the part's declared Content Type; a generic .xml part used as a ticket with default application/xml content type; package repair tools that preserve relationships but re-create parts with wrong types.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/ca5f23b0a511bd8b. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Documents/FixedSchema.cs:561

            checkRels = part.GetRelationshipsByType(_printTicketRel);
            count = 0;
            foreach (PackageRelationship rel in checkRels)
            {
                count++;
                if (count > 1)
                {
                    throw new FileFormatException(SR.XpsValidatingLoaderMoreThanOnePrintTicketPart);
                }

                // Also check for existence and type
                Uri targetUri = PackUriHelper.ResolvePartUri(partUri, rel.TargetUri);
                Uri absTargetUri = PackUriHelper.Create(packageUri, targetUri);

                PackagePart targetPart = package.GetPart(targetUri);

                if (!_printTicketContentType.AreTypeAndSubTypeEqual(new ContentType(targetPart.ContentType)))
                {
                    throw new FileFormatException(SR.XpsValidatingLoaderPrintTicketHasIncorrectType);
                }
            }

            checkRels = part.GetRelationshipsByType(_thumbnailRel);
            count = 0;
            foreach (PackageRelationship rel in checkRels)
            {
                count++;
                if (count > 1)
                {
                    throw new FileFormatException(SR.XpsValidatingLoaderMoreThanOneThumbnailPart);
                }

                // Also check for existence and type
                Uri targetUri = PackUriHelper.ResolvePartUri(partUri, rel.TargetUri);
                Uri absTargetUri = PackUriHelper.Create(packageUri, targetUri);

                PackagePart targetPart = package.GetPart(targetUri);

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