dotnet/wpf · error · ArgumentException

SR.DataGrid_InvalidColumnReuse

Error message

SR.DataGrid_InvalidColumnReuse

What it means

DataGridColumnCollection.InsertItem throws ArgumentException with DataGrid_InvalidColumnReuse when the inserted column's DataGridOwner is already set, i.e. the column instance already belongs to another DataGrid. A DataGridColumn can only be hosted by one DataGrid at a time.

Solutions

1. Create a new DataGridColumn instance for each grid
2. Remove the column from the previous grid's Columns before re-adding it elsewhere
3. Clone the column's settings into a fresh instance when sharing configuration
4. Never cache column instances for reuse across grids

Example fix

// before
var col = new DataGridTextColumn { Header = "Name", Binding = new Binding("Name") };
gridA.Columns.Add(col);
gridB.Columns.Add(col); // reuse
// after
gridA.Columns.Add(new DataGridTextColumn { Header = "Name", Binding = new Binding("Name") });
gridB.Columns.Add(new DataGridTextColumn { Header = "Name", Binding = new Binding("Name") });

if (column.DataGridOwner != null)
    throw new InvalidOperationException("Column already belongs to a DataGrid; create a new instance.");

bool IsReusable(DataGridColumn c) => c.DataGridOwner == null;

When it happens

Trigger: Adding the same DataGridColumn instance (or one from another grid) to a second DataGrid.Columns collection; moving a column between grids without removing it first.

Common situations: Reusing a shared column instance across multiple grids; copying columns between grids by reference instead of creating new instances; moving columns between two grids on the same page.

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

• SR.PropertyNotSupported
• Animation_ChildMustBeKeyFrame
• Animation_DependencyPropertyIsNotAnimatable
• Animation_UnrecognizedHandoffBehavior
• Can only call SelectAll when CanSelectMultipleItems is true.

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/e1c21f8442aebcc2. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/DataGridColumnCollection.cs:45

            RebuildRealizedColumnsBlockListForNonVirtualizedRows = true;

            RealizedColumnsBlockListForVirtualizedRows = null;
            RealizedColumnsDisplayIndexBlockListForVirtualizedRows = null;
            RebuildRealizedColumnsBlockListForVirtualizedRows = true;
        }

        #region Protected Overrides

        protected override void InsertItem(int index, DataGridColumn item)
        {
            if (item == null)
            {
                throw new ArgumentNullException(nameof(item), SR.DataGrid_NullColumn);
            }

            if (item.DataGridOwner != null)
            {
                throw new ArgumentException(SR.Format(SR.DataGrid_InvalidColumnReuse, item.Header), nameof(item));
            }

            if (DisplayIndexMapInitialized)
            {
                ValidateDisplayIndex(item, item.DisplayIndex, true);
            }

            base.InsertItem(index, item);
            item.CoerceValue(DataGridColumn.IsFrozenProperty);
        }

        protected override void SetItem(int index, DataGridColumn item)
        {
            if (item == null)
            {
                throw new ArgumentNullException(nameof(item), SR.DataGrid_NullColumn);
            }

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