SR.TableCollectionRankMultiDimNotSupported

Error message

SR.TableCollectionRankMultiDimNotSupported

What it means

ContentElementCollection.CopyTo requires a single-dimensional array target; ICollection.CopyTo contract in this WPF collection only supports rank-1 arrays. Passing a multi-dimensional array (Rank != 1) throws ArgumentException with TableCollectionRankMultiDimNotSupported. It is a pre-copy argument validation failure before any elements are copied.

Solutions

Copy into a single-dimensional array instead (e.g. ContentElement[] or object[])
Convert a multidimensional source with a manual loop flattening elements before CopyTo
If using LINQ helpers like ToArray/ToList, they already allocate rank-1 arrays — switch to those

Example fix

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

Defensive patterns

Strategy: validation

Validate before calling

if (array == null) throw new ArgumentNullException(nameof(array));
if (array.Rank != 1) throw new ArgumentException("Collection supports only single-dimensional arrays", nameof(array));
collection.CopyTo(array, index);

Type guard

bool IsRankOneArray(Array a) => a != null && a.Rank == 1;

Try / catch

try { collection.CopyTo(array, index); }
catch (ArgumentException ex) when (ex.Message.Contains("multi"))
{
    var flat = new object[collection.Count];
    collection.CopyTo(flat, index);
}

Prevention

Always allocate rank-1 arrays for CopyTo targets
Use ToArray()/ToList() instead of manual CopyTo where possible
Flatten multidimensional sources manually before copying

When it happens

Trigger: Calling CopyTo (explicitly or via ICollection.CopyTo, SerializationInfo, LINQ copy helpers) on a ContentElementCollection (e.g. TableCell blocks/text elements) with a 2D array like new object[2,2].

Common situations: Legacy code written for APIs that accept multidimensional arrays; generic serialization helpers that allocate Array.CreateInstance(typeof(object), lengths) with multiple lengths; interop with COM or older collection code that used rectangular arrays.

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

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/59a29890fb5ea1c0. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/documents/ContentElementCollection.cs:69

        /// <see cref="ICollection.CopyTo"/>
        /// </summary>
        /// <exception cref="ArgumentNullException">
        /// <see cref="ICollection.CopyTo"/>
        /// </exception>
        /// <exception cref="ArgumentException">
        /// <see cref="ICollection.CopyTo"/>
        /// </exception>
        /// <exception cref="ArgumentOutOfRangeException">
        /// <see cref="ICollection.CopyTo"/>
        /// </exception>
        /// <param name="array"><see cref="ICollection.CopyTo"/></param>
        /// <param name="index"><see cref="ICollection.CopyTo"/></param>
        public void CopyTo(Array array, int index)
        {
            ArgumentNullException.ThrowIfNull(array);
            if (array.Rank != 1)
            {
                throw new ArgumentException(SR.TableCollectionRankMultiDimNotSupported);
            }
            if (index < 0)
            {
                throw new ArgumentOutOfRangeException(nameof(index), SR.TableCollectionOutOfRangeNeedNonNegNum);
            }
            if (array.Length - index < Size)
            {
                throw new ArgumentException(SR.TableCollectionInvalidOffLen);
            }

            Array.Copy(Items, 0, array, index, Size);
        }

        /// <summary>
        /// Strongly typed version of ICollection.CopyTo.
        /// </summary>
        /// <exception cref="ArgumentNullException">
        /// <see cref="ICollection.CopyTo"/>

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