Unity-Technologies/UnityCsReference · error · ArgumentException

The maximum number of sorted columns is {state.maximumNumber

Error message

The maximum number of sorted columns is {state.maximumNumberOfSortedColumns}. Trying to set {columnIndices.Length} columns.

What it means

Thrown by SetSortingColumns when the number of sorted columns exceeds state.maximumNumberOfSortedColumns. The header only supports a bounded number of simultaneous sort keys for performance and display reasons.

Source

Thrown at Editor/Mono/GUI/TreeView/MultiColumnHeader.cs:81

        public MultiColumnHeader(MultiColumnHeaderState state)
        {
            m_State = state;
            m_HeaderButtonsControlID = GUIUtility.GetPermanentControlID();
        }

        public void SetSortingColumns(int[] columnIndices, bool[] sortAscending)
        {
            if (columnIndices == null)
                throw new ArgumentNullException("columnIndices");

            if (sortAscending == null)
                throw new ArgumentNullException("sortAscending");

            if (columnIndices.Length != sortAscending.Length)
                throw new ArgumentException("Input arrays should have same length");

            if (columnIndices.Length > state.maximumNumberOfSortedColumns)
                throw new ArgumentException("The maximum number of sorted columns is " + state.maximumNumberOfSortedColumns + ". Trying to set " + columnIndices.Length + " columns.");

            if (columnIndices.Length != columnIndices.DistinctCount())
                throw new ArgumentException("Duplicate column indices are not allowed", "columnIndices");

            bool changed = false;

            if (!columnIndices.AsSpan().SequenceEqual(state.sortedColumns))
            {
                state.sortedColumns = columnIndices;
                changed = true;
            }

            for (int i = 0; i < columnIndices.Length; ++i)
            {
                var column = GetColumn(columnIndices[i]);
                if (column.sortedAscending != sortAscending[i])
                {
                    column.sortedAscending = sortAscending[i];

View on GitHub (pinned to 225b0fbdb5)

Solutions

Limit the sort columns to the first N where N <= state.maximumNumberOfSortedColumns.
Raise maximumNumberOfSortedColumns if the use case genuinely needs more sort keys.
Validate against the cap before persisting user sort preferences.

Example fix

// before
header.SetSortingColumns(cols, flags); // cols.Length > max

// after
int max = header.state.maximumNumberOfSortedColumns;
header.SetSortingColumns(cols.Take(max).ToArray(), flags.Take(max).ToArray());

Defensive patterns

Strategy: validation

Validate before calling

int max = header.state.maximumNumberOfSortedColumns; var cappedCols = columnIndices.Take(max).ToArray(); var cappedFlags = sortAscending.Take(max).ToArray();

Prevention

Read maximumNumberOfSortedColumns before building the sort arrays.
Persist sort state only after validating against the current cap.
Document the cap to users in the multi-sort UI.

When it happens

Trigger: Passing more sort columns than maximumNumberOfSortedColumns (typically 3); restoring a saved sort configuration that was created with a higher limit.

Common situations: Changing maximumNumberOfSortedColumns to a lower value but retaining old persisted sort state; a feature that adds multi-level sorting beyond the configured cap.

Related errors

AI-assisted analysis of Unity-Technologies/UnityCsReference@225b0fbdb5 (2026-08-13). Data as JSON: /api/errors/894ca71be26d3adb. Report an issue: GitHub.