dotnet/wpf · error · ArgumentException

SR.Format(SR.CollectionNumberOfElementsMustBeLessOrEqualTo…

Error message

SR.Format(SR.CollectionNumberOfElementsMustBeLessOrEqualTo, MaxGlyphCount)

What it means

GlyphRun.Initialize caps the number of glyphs at MaxGlyphCount because very large runs can overflow native resources; exceeding it throws ArgumentException stating the collection must have at most MaxGlyphCount elements, naming glyphIndices.

Solutions

  1. Split the text into smaller runs (per line or per paragraph) each under MaxGlyphCount
  2. Use TextFormatter/TextSource-based layout which chunks runs naturally
  3. Check glyphIndices.Count <= MaxGlyphCount before construction and paginate

Example fix

// before: one run for 100k glyphs
// after
foreach (var chunk in ChunkGlyphs(glyphs, MaxGlyphCount))
    dc.DrawGlyphRun(foreground, MakeRun(chunk));
Defensive patterns

Strategy: validation

Validate before calling

if (glyphIndices.Count > GlyphRun.MaxGlyphCount)
    glyphIndices = SplitIntoChunks(glyphIndices, GlyphRun.MaxGlyphCount); // draw in batches

Type guard

static bool WithinMaxGlyphs(ICollection<ushort> glyphs) => glyphs != null && glyphs.Count <= GlyphRun.MaxGlyphCount;

Try / catch

try { var run = new GlyphRun(...); }
catch (ArgumentException ex) when (ex.ParamName == "glyphIndices" && ex.Message.Contains("less or equal")) { /* split and redraw */ }

Prevention

When it happens

Trigger: Calling the GlyphRun constructor, TryCreate, or EndInit with glyphIndices.Count > MaxGlyphCount — e.g. shaping an entire large document into a single run instead of per-line/per-paragraph runs.

Common situations: Batch-rendering thousands of glyphs in one run in custom text-layout code; caching a whole page of shaped text as one GlyphRun.

Understand the failure class

Background: "File too large" / "file size exceeds limit" errors: why libraries cap file sizes and how to fix them — this error's family across 46 libraries.

Related errors

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/311cc9d39b8e4fe8. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media/GlyphRun.cs:437

                // maximum size allowed before rendering falls back to using geometry.
                // This was done in order to produce a managed exception where we might
                // hit overflow or memory allocation issues in native code.
                // We no longer own the code the produces these bitmaps so we can't reliably
                // avoid the issue here any longer.
            }
            else
            {
                ArgumentOutOfRangeException.ThrowIfEqual(renderingEmSize, double.NaN);
                ArgumentOutOfRangeException.ThrowIfNegative(renderingEmSize);
                ArgumentNullException.ThrowIfNull(glyphTypeface);
                ArgumentNullException.ThrowIfNull(glyphIndices);

                if (glyphIndices.Count <= 0)
                    throw new ArgumentException(SR.CollectionNumberOfElementsMustBeGreaterThanZero, nameof(glyphIndices));

                if (glyphIndices.Count > MaxGlyphCount)
                {
                    throw new ArgumentException(SR.Format(SR.CollectionNumberOfElementsMustBeLessOrEqualTo, MaxGlyphCount), nameof(glyphIndices));
                }

                ArgumentNullException.ThrowIfNull(advanceWidths);

                if (advanceWidths.Count != glyphIndices.Count)
                    throw new ArgumentException(SR.Format(SR.CollectionNumberOfElementsShouldBeEqualTo, glyphIndices.Count), nameof(advanceWidths));

                if (glyphOffsets != null && glyphOffsets.Count != 0 && glyphOffsets.Count != glyphIndices.Count)
                    throw new ArgumentException(SR.Format(SR.CollectionNumberOfElementsShouldBeEqualTo, glyphIndices.Count), nameof(glyphOffsets));

                // We should've caught all invalid cases above and thrown appropriate exceptions.
                Invariant.Assert(false);
            }

            IsInitialized = true; // The glyphrun is completely initialized
        }

        #endregion Constructors

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