dotnet/wpf · error · ArgumentException

SR.Format(SR.InvalidCtorParameterNoNaN, "value")

Error message

SR.Format(SR.InvalidCtorParameterNoNaN, "value")

What it means

The FigureLength(double, FigureUnitType) constructor rejects a value that is double.NaN. FigureLength describes a figure's width/height and NaN is not a representable length; the constructor throws ArgumentException with InvalidCtorParameterNoNaN.

Solutions

Validate the value with double.IsNaN before constructing and substitute a valid value or FigureUnitType.Auto.
Use FigureLength.Auto (or FigureUnitType.Auto) instead of NaN to express 'auto' sizing.
Trace the source of the NaN (division by zero, uninitialized field, parse failure) and fix the upstream computation.

Example fix

// before
var length = new FigureLength(computedValue, FigureUnitType.Pixel); // NaN throws

// after
var length = double.IsNaN(computedValue)
    ? FigureLength.Auto
    : new FigureLength(computedValue, FigureUnitType.Pixel);

Defensive patterns

Strategy: validation

Validate before calling

if (double.IsNaN(value))
    throw new ArgumentException("value must not be NaN.");
var length = new FigureLength(value, unit);

Type guard

bool IsValidFigureLength(double v) => !double.IsNaN(v) && !double.IsInfinity(v) && v >= 0;

Try / catch

try { var len = new FigureLength(value, unit); }
catch (ArgumentException) { /* fall back to FigureLength.Auto */ }

Prevention

Use FigureLength.Auto instead of NaN for auto sizing.
Validate computed values before constructing lengths.
Trace and eliminate NaN sources (0/0 division, uninitialized fields).

When it happens

Trigger: Calling new FigureLength(double.NaN, ...) — e.g. passing an unbound computed value or a default field never initialized to a real number — with any FigureUnitType.

Common situations: Propagating NaN from parsed input or division results; using double.NaN as a sentinel for 'auto' instead of FigureUnitType.Auto; databound or computed values not validated before constructing the length.

Related errors

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/d8f951022cf73622. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/FigureLength.cs:103

        /// instance.</param>
        /// <remarks> 
        /// If the <c>type</c> parameter is <c>FigureUnitType.Auto</c>, 
        /// then passed in value is ignored and replaced with <c>0</c>.
        /// </remarks>
        /// <exception cref="ArgumentException">
        /// If <c>value</c> parameter is <c>double.NaN</c>
        /// or <c>value</c> parameter is <c>double.NegativeInfinity</c>
        /// or <c>value</c> parameter is <c>double.PositiveInfinity</c>.
        /// or <c>value</c> parameter is <c>negative</c>.
        /// </exception>
        public FigureLength(double value, FigureUnitType type)
        {
            double maxColumns = PTS.Restrictions.tscColumnRestriction;
            double maxPixel = Math.Min(1000000, PTS.MaxPageSize);

            if (double.IsNaN(value))
            {
                throw new ArgumentException(SR.Format(SR.InvalidCtorParameterNoNaN, "value"));
            }
            if (double.IsInfinity(value))
            {
                throw new ArgumentException(SR.Format(SR.InvalidCtorParameterNoInfinity, "value"));
            }
            if (value < 0.0)
            {
                throw new ArgumentOutOfRangeException(SR.Format(SR.InvalidCtorParameterNoNegative, "value"));
            }
            if (    type != FigureUnitType.Auto
                &&  type != FigureUnitType.Pixel
                &&  type != FigureUnitType.Column
                &&  type != FigureUnitType.Content
                &&  type != FigureUnitType.Page   )
            {
                throw new ArgumentException(SR.Format(SR.InvalidCtorParameterUnknownFigureUnitType, "type"));
            }
            if (type is FigureUnitType.Content or FigureUnitType.Page)

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