spectreconsole/spectre.console · error · ArgumentNullException

Value cannot be null. (Parameter 'content')

Error message

Value cannot be null. (Parameter 'content')

What it means

Thrown by the TableCell(IRenderable) constructor when the content argument is null. A cell must contain a renderable. The string overload coalesces null markup to string.Empty via new Markup(markup ?? string.Empty), so it tolerates null.

Source

Thrown at src/Spectre.Console/Widgets/Table/TableCell.cs:24

public sealed class TableCell : IRenderable
{
    /// <summary>
    /// Gets the cell content.
    /// </summary>
    public IRenderable Content { get; }

    /// <summary>
    /// Gets the number of columns this cell spans.
    /// </summary>
    public int ColumnSpan { get; set; }

    /// <summary>
    /// Initializes a new instance of the <see cref="TableCell"/> class.
    /// </summary>
    /// <param name="content">The cell content.</param>
    public TableCell(IRenderable content)
    {
        Content = content ?? throw new ArgumentNullException(nameof(content));
        ColumnSpan = 1;
    }

    /// <summary>
    /// Initializes a new instance of the <see cref="TableCell"/> class.
    /// </summary>
    /// <param name="markup">Markup text.</param>
    public TableCell(string markup)
        : this(new Markup(markup ?? string.Empty))
    {
    }

    /// <summary>
    /// Sets the number of columns this cell should span.
    /// </summary>
    /// <param name="span">The number of columns to span.</param>
    /// <returns>The same instance so that multiple calls can be chained.</returns>
    public TableCell Span(int span)

View on GitHub (pinned to 0acc92fada)

Solutions

1. Pass a non-null IRenderable.
2. Use the string overload 'new TableCell(markup)' which tolerates null.
3. Coalesce with '?? new Markup(string.Empty)'.

Example fix

// before
var cell = new TableCell(maybeNullRenderable);

// after
var cell = new TableCell(maybeNullRenderable ?? new Markup(string.Empty));

if (content is null) throw new ArgumentNullException(nameof(content));
var cell = new TableCell(content);

static bool HasValidCellContent(IRenderable? content) => content is not null;

When it happens

Trigger: Constructing 'new TableCell((IRenderable)null)' or passing a null IRenderable variable.

Common situations: Content renderable obtained from a method that can return null, or a conditional expression that yields null.

Related errors

• Value cannot be null. (Parameter 'content')
• Value cannot be null. (Parameter 'text')
• Value cannot be null. (Parameter 'children')
• Value cannot be null. (Parameter 'title')
• Must be > 1

AI-assisted analysis of spectreconsole/spectre.console@0acc92fada (2026-08-13). Data as JSON: /api/errors/54cae398de874723. Report an issue: GitHub.