dotnet/wpf · error · ArgumentException

SR.Collection_BadRank

Error message

SR.Collection_BadRank

What it means

VectorCollection.CopyTo(Array array, int index) requires the destination to be a single-dimensional Array with enough room starting at index (it also validates index >= 0 and index <= array.Length - Count beforehand). If array.Rank != 1 — i.e., a multidimensional array was supplied — it throws ArgumentException(SR.Collection_BadRank), mirroring BCL collection behavior.

Solutions

1. Allocate a one-dimensional Vector[] (or Array) with length >= index + collection.Count and pass that to CopyTo
2. Add a guard (array.Rank == 1) before calling CopyTo and handle multidimensional destinations with a manual loop
3. If a 2D layout is required, copy into a 1D array first and then reshape manually

Example fix

// before
var dest = new Vector[rows, cols];
collection.CopyTo(dest, 0);
// after
var dest = new Vector[collection.Count];
collection.CopyTo(dest, 0);

if (dest == null) throw new ArgumentNullException(nameof(dest));
if (dest.Rank != 1) throw new ArgumentException("Destination array must be one-dimensional.", nameof(dest));
if (index < 0 || index > dest.Length - vectorCollection.Count) throw new ArgumentOutOfRangeException(nameof(index));

static bool CanCopyTo(VectorCollection c, Array a, int i) => a != null && a.Rank == 1 && i >= 0 && i <= a.Length - c.Count;

try { collection.CopyTo(dest, index); }
catch (ArgumentException ex) { /* dest was multidimensional (or wrong bounds); allocate a 1D array and retry */ }

When it happens

Trigger: Calling ((ICollection)vectorCollection).CopyTo(multiDimArray, i) with a 2D (or higher-rank) array; also triggered if index is negative or larger than array.Length - Count via the preceding ArgumentOutOfRangeException checks.

Common situations: Generic copy-to-array helper code written against Array that happens to allocate rectangular arrays; porting code that used a 2D grid as scratch storage; interop code reusing buffers across calls.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• Collection_CopyTo_ArrayCannotBeMultidimensional
• Collection_CopyTo_ArrayCannotBeMultidimensional
• Collection_CopyTo_IndexGreaterThanOrEqualToArrayLength
• Collection_CopyTo_IndexGreaterThanOrEqualToArrayLength
• Collection_CopyTo_NumberOfElementsExceedsArrayLength

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/08e7d4737daa0cdd. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media/Generated/VectorCollection.cs:367

        #endregion

        #region ICollection

        void ICollection.CopyTo(Array array, int index)
        {
            ReadPreamble();

            ArgumentNullException.ThrowIfNull(array);

            // This will not throw in the case that we are copying
            // from an empty collection.  This is consistent with the
            // BCL Collection implementations. (Windows 1587365)
            ArgumentOutOfRangeException.ThrowIfNegative(index);
            ArgumentOutOfRangeException.ThrowIfGreaterThan(index, array.Length - _collection.Count);

            if (array.Rank != 1)
            {
                throw new ArgumentException(SR.Collection_BadRank);
            }

            // Elsewhere in the collection we throw an AE when the type is
            // bad so we do it here as well to be consistent
            try
            {
                int count = _collection.Count;
                for (int i = 0; i < count; i++)
                {
                    array.SetValue(_collection[i], index + i);
                }
            }
            catch (InvalidCastException e)
            {
                throw new ArgumentException(SR.Format(SR.Collection_BadDestArray, this.GetType().Name), e);
            }
        }

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