dotnet/wpf · error · ArgumentException

SR.SelectedCellsCollection_InvalidItem

Error message

SR.SelectedCellsCollection_InvalidItem

What it means

DataGrid.SelectedCellsCollection.Add throws ArgumentException (SelectedCellsCollection_InvalidItem) when the DataGridCellInfo passed does not belong to the DataGrid's items/columns — IsValidPublicCell checks that the cell references a valid item and column of the owning DataGrid.

Solutions

1. Build DataGridCellInfo only from (item, column) pairs that exist in the target DataGrid's Items and Columns collections.
2. Re-resolve saved selections against the current grid after rebinding instead of reusing stale DataGridCellInfo objects.
3. Avoid sharing cell info objects across DataGrid instances.

Example fix

// before
cell = new DataGridCellInfo(otherGridItem, column);
dg.SelectedCells.Add(cell);
// after
var item = dg.Items.Contains(otherGridItem) ? otherGridItem : null;
var col = dg.Columns.Contains(column) ? column : null;
if (item != null && col != null) dg.SelectedCells.Add(new DataGridCellInfo(item, col));

if (dg.Items.Contains(item) && dg.Columns.Contains(column))
    dg.SelectedCells.Add(new DataGridCellInfo(item, column));

bool IsValidCell(DataGridCellInfo c, DataGrid dg) => dg.Items.Contains(c.Item) && (c.Column == null || dg.Columns.Contains(c.Column));

try { dg.SelectedCells.Add(cell); } catch (ArgumentException) { /* cell not in this grid; skip */ }

When it happens

Trigger: Calling dataGrid.SelectedCells.Add(cellInfo) with a DataGridCellInfo constructed from an item not in the grid's Items, a column not in its Columns, or a cellInfo from another DataGrid instance.

Common situations: Programmatically restoring selection state persisted from another grid or session, or building DataGridCellInfo manually with mismatched item/column references after the grid was re-bound.

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

• ArgumentOutOfRangeException (timeout was Duration.Automatic)
• Can only call SelectAll when CanSelectMultipleItems is true.
• Collection_BadRank
• Collection_CopyTo_ArrayCannotBeMultidimensional
• Collection_CopyTo_ArrayCannotBeMultidimensional

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/e12188af32018e75. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/VirtualizedCellInfoCollection.cs:69

        }

        #endregion

        #region IList<T> Members

        /// <summary>
        ///     Adds a cell to the list.
        /// </summary>
        /// <param name="cell">The cell to add.</param>
        public void Add(DataGridCellInfo cell)
        {
            _owner.Dispatcher.VerifyAccess();

            ValidateIsReadOnly();

            if (!IsValidPublicCell(cell))
            {
                throw new ArgumentException(SR.SelectedCellsCollection_InvalidItem, nameof(cell));
            }

            if (Contains(cell))
            {
                throw new ArgumentException(SR.SelectedCellsCollection_DuplicateItem, nameof(cell));
            }

            AddValidatedCell(cell);
        }

        /// <summary>
        ///     Adds a validated cell to the list.
        /// </summary>
        /// <param name="cell">The cell to add.</param>
        internal void AddValidatedCell(DataGridCellInfo cell)
        {
            Debug.Assert(IsValidCell(cell), "The cell should be valid.");
            Debug.Assert(!Contains(cell), "VirtualizedCellInfoCollection does not support duplicate items.");

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