What causes "SR.GridCollection_DestArrayInvalidRank" in dotnet/wpf?

Pass a single-dimensional array, e.g. new RowDefinition[grid.RowDefinitions.Count].

dotnet/wpf · error · ArgumentException

SR.GridCollection_DestArrayInvalidRank

Error message

SR.GridCollection_DestArrayInvalidRank

What it means

RowDefinition's explicit ICollection.CopyTo implementation validates the destination array before copying. A multi-dimensional (Rank != 1) array cannot be used as the copy destination, so it throws ArgumentException(SR.GridCollection_DestArrayInvalidRank).

Solutions

Pass a single-dimensional array, e.g. new RowDefinition[grid.RowDefinitions.Count].
Cast multidimensional data to a flat 1D array first.
Add a Rank == 1 check in calling code to fail early with a clearer message.

Example fix

// before
var dest = new RowDefinition[rows, 1];
((ICollection)grid.RowDefinitions).CopyTo(dest, 0);
// after
var dest = new RowDefinition[grid.RowDefinitions.Count];
((ICollection)grid.RowDefinitions).CopyTo(dest, 0);

Defensive patterns

Strategy: type-guard

Validate before calling

if (dest == null) throw new ArgumentNullException(nameof(dest));
if (dest.Rank != 1) dest = new RowDefinition[grid.RowDefinitions.Count];
((ICollection)grid.RowDefinitions).CopyTo(dest, 0);

Type guard

bool IsSingleDimensional(Array a) => a.Rank == 1;

Try / catch

try { ((ICollection)grid.RowDefinitions).CopyTo(dest, 0); }
catch (ArgumentException) { dest = new RowDefinition[grid.RowDefinitions.Count]; ((ICollection)grid.RowDefinitions).CopyTo(dest, 0); }

Prevention

Always allocate one-dimensional arrays for ICollection.CopyTo destinations.
Avoid generic Array-typed scratch buffers that may be multidimensional.
Use the strongly-typed CopyTo/ToArray style helpers when available.

When it happens

Trigger: Calling CopyTo (or collection initializers / APIs that use it) on a RowDefinitionCollection with a 2D array: ((ICollection)grid.RowDefinitions).CopyTo(twoDimArray, 0).

Common situations: Reusing a Rect[,] or object[,] scratch array for the copy; generic serialization code that allocates multidimensional arrays; interop code assuming any Array works.

Related errors

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/a800c4fc064d4ecc. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/RowDefinition.cs:73

        #endregion Constructors

        //------------------------------------------------------
        //
        //  Public Methods
        //
        //------------------------------------------------------

        #region Public Methods

        /// <summary>
        ///     <see cref="ICollection.CopyTo"/>
        /// </summary>
        void ICollection.CopyTo(Array array, int index)
        {
            ArgumentNullException.ThrowIfNull(array);
            if (array.Rank != 1)
            {
                throw new ArgumentException(SR.GridCollection_DestArrayInvalidRank);
            }
            if (index < 0)
            {
                throw new ArgumentOutOfRangeException(SR.Format(SR.GridCollection_DestArrayInvalidLowerBound, "index"));
            }
            if (array.Length - index < _size)
            {
                throw new ArgumentException(SR.Format(SR.GridCollection_DestArrayInvalidLength, "array"));
            }

            if (_size > 0)
            {
                Debug.Assert(_items != null);
                Array.Copy(_items, 0, array, index, _size);
            }
        }

        /// <summary>

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