spectreconsole/spectre.console · error · InvalidOperationException

The number of row columns (including spans) are greater…

Error message

The number of row columns (including spans) are greater than the number of table columns. Expected {_table.Columns.Count} but got {totalSpan}.

What it means

When adding a row (AddRow overloads), CreateRow sums each cell's contribution: a plain IRenderable counts as 1, a TableCell counts as its ColumnSpan. If the total exceeds the number of columns defined on the table, it throws InvalidOperationException. Note the asymmetric behavior: fewer cells than columns is allowed (the method pads with empty Text cells), but more is rejected. The message wording ('are greater than') is slightly ungrammatical.

Solutions

1. Ensure table columns count >= total row span before adding rows: add missing AddColumn calls first.
2. Reduce the cells in the row, or lower a TableCell span, so the sum <= table.Columns.Count.
3. If rows may have fewer cells, rely on the built-in padding (do nothing) — only excess throws.
4. Compute span as min(requestedSpan, table.Columns.Count - otherCells).

Example fix

// before
var table = new Table();
table.AddColumns("A", "B", "C");
table.AddRow(new TableCell("wide").Span(3), new Markup("extra")); // total 4 > 3

// after
var table = new Table();
table.AddColumns("A", "B", "C", "D");
table.AddRow(new TableCell("wide").Span(3), new Markup("extra")); // total 4 == 4

int totalSpan = rowCells.Sum(c => c is TableCell tc ? tc.ColumnSpan : 1);
if (totalSpan > table.Columns.Count)
    table.AddColumns(Enumerable.Range(0, totalSpan - table.Columns.Count).Select(_ => string.Empty).ToArray());
table.AddRow(rowCells);

When it happens

Trigger: Defining N columns via AddColumn/AddColumns but adding a row whose cells/spans sum to > N — e.g. 3 columns but a row with 4 cells, or a TableCell.Span(3) plus two more plain cells (total 4) against 3 columns.

Common situations: Forgetting to AddColumn(s) before AddRow; mismatched counts after dynamically adding/removing columns; a spanning cell computed from data whose span pushes the total over; building rows from a 2D array whose width exceeds the declared columns.

Related errors

• Column spanning is not supported in table
• Column spanning is not supported in table footer rows.
• Column spanning is not supported in table header rows.
• Cannot add new columns to table with existing rows.
• Column span must be at least 1.

AI-assisted analysis of spectreconsole/spectre.console@0acc92fada (2026-08-13). Data as JSON: /api/errors/7012fdc536a64ed2. Report an issue: GitHub.

Appendix: source

Thrown at src/Spectre.Console/Widgets/Table/TableRowCollection.cs:195

        // Calculate total span considering TableCell instances
        var totalSpan = 0;
        for (var i = 0; i < row.Count; i++)
        {
            var cell = row[i];
            if (cell is TableCell tableCell)
            {
                totalSpan += tableCell.ColumnSpan;
            }
            else
            {
                totalSpan++;
            }
        }

        if (totalSpan > _table.Columns.Count)
        {
            throw new InvalidOperationException($"The number of row columns (including spans) are greater than the number of table columns. Expected {_table.Columns.Count} but got {totalSpan}.");
        }

        // Need to add missing columns
        if (totalSpan < _table.Columns.Count)
        {
            var diff = _table.Columns.Count - totalSpan;
            Enumerable.Range(0, diff).ForEach(_ => row.Add(Text.Empty));
        }

        return row;
    }
}

View on GitHub (pinned to 0acc92fada)