dotnet/wpf · error · ObjectDisposedException

SR.HyphenatorDisposed

Error message

SR.HyphenatorDisposed

What it means

NaturalLanguageHyphenator.AnalyzeText throws ObjectDisposedException with SR.HyphenatorDisposed when the hyphenator's native resource has already been released via Dispose. Once disposed, the native NlHyphenate handle (_hyphenatorResource) is invalid, so the API refuses to run rather than corrupt memory or crash native code.

Solutions

1. Stop using the hyphenator instance after calling Dispose; create a new NaturalLanguageHyphenator for subsequent analysis
2. Check the _disposed/IsDisposed state before calling AnalyzeText, or guard with try-catch for ObjectDisposedException
3. Fix disposal ordering so text layout/hyphenation finishes before the hyphenator is disposed

Example fix

// before
hyphenator.Dispose();
var positions = hyphenator.AnalyzeText(text, length);
// after
var positions = hyphenator.AnalyzeText(text, length);
hyphenator.Dispose();

if (hyphenator == null) return null; // also avoid use after Dispose by tracking lifetime

bool IsUsable(NaturalLanguageHyphenator h) => h != null && !h.IsDisposed;

try { return hyphenator.AnalyzeText(text, length); } catch (ObjectDisposedException) { return null; }

When it happens

Trigger: Calling AnalyzeText on a hyphenator instance after Dispose() has been called on it; typically reusing a cached/static hyphenator whose Dispose ran during teardown or page unload while text layout still runs.

Common situations: Hyphenation enabled on a TextBox/FlowDocument while the owning document or control is being disposed on a background or layout thread; races where one component disposes the shared hyphenator while another still formats text.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

• EncryptedPackageEnvelope object was disposed.
• FixedPageReader
• NLGSpellerInterop.SpellerSegment
• NLGSpellerInterop.SpellerSentence
• SR.ByteRangeDownloaderDisposed

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/909b1a03b3b86f73. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Documents/NaturalLanguageHyphenator.cs:121

            CultureInfo     textCulture
            )
        {
            Invariant.Assert(
                    characterSource != null
                &&  characterSource.Length > 0
                &&  length > 0
                &&  length <= characterSource.Length
                );

            if (_hyphenatorResource == IntPtr.Zero)
            {
                // No hyphenator available, no service delivered
                return null;
            }

            if (_disposed)
            {
                throw new ObjectDisposedException(SR.HyphenatorDisposed);
            }

            byte[] isHyphenPositions = new byte[(length + 7) / 8];

            UnsafeNativeMethods.NlHyphenate(
                _hyphenatorResource,
                characterSource,
                length,
                ((textCulture != null && textCulture != CultureInfo.InvariantCulture) ? textCulture.LCID : 0),
                isHyphenPositions,
                isHyphenPositions.Length
                );

            return new HyphenBreaks(isHyphenPositions, length);
        }

        /// <summary>
        /// Private implementation of TextLexicalBreaks that encapsulates hyphen opportunities within

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