dotnet/wpf · error · ArgumentException

Microsoft.Windows.Controls.SR.Format(Microsoft.Windows.Contr…

Error message

Microsoft.Windows.Controls.SR.Format(Microsoft.Windows.Controls.SR.InvalidCtorParameterUnknownRibbonControlLengthUnitType, "type")

What it means

The RibbonControlLength(value, type) constructor throws this ArgumentException when type is not a recognized RibbonControlLengthUnitType value (Auto, Pixel, Star or the sentinel). An undefined enum value passed to the constructor is rejected immediately, signaling a programming error.

Solutions

1. Use one of the defined RibbonControlLengthUnitType values (Auto, Pixel, Star)
2. Ensure the type argument is not an uninitialized or cast-invalid enum value
3. Default to RibbonControlLengthUnitType.Pixel when the type is unknown

When it happens

Trigger: Thrown at src/Microsoft.DotNet.Wpf/src/System.Windows.Controls.Ribbon/Microsoft/Windows/Controls/Ribbon/RibbonControlLength.cs:63 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/a1418540f7b35773. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/System.Windows.Controls.Ribbon/Microsoft/Windows/Controls/Ribbon/RibbonControlLength.cs:63

        /// </summary>
        public RibbonControlLength(double value, RibbonControlLengthUnitType type)
        {
            if (double.IsNaN(value))
            {
                throw new ArgumentException(Microsoft.Windows.Controls.SR.Format(Microsoft.Windows.Controls.SR.InvalidCtorParameterNoNaN, "value"));
            }

            if (type == RibbonControlLengthUnitType.Star && double.IsInfinity(value))
            {
                throw new ArgumentException(Microsoft.Windows.Controls.SR.Format(Microsoft.Windows.Controls.SR.InvalidCtorParameterNoInfinityForStarSize, "value"));
            }

            if (type != RibbonControlLengthUnitType.Auto
                && type != RibbonControlLengthUnitType.Pixel
                && type != RibbonControlLengthUnitType.Item
                && type != RibbonControlLengthUnitType.Star)
            {
                throw new ArgumentException(Microsoft.Windows.Controls.SR.Format(Microsoft.Windows.Controls.SR.InvalidCtorParameterUnknownRibbonControlLengthUnitType, "type"));
            }

            _unitValue = (type == RibbonControlLengthUnitType.Auto) ? 0.0 : value;
            _unitType = type;
        }

        #endregion

        #region Public Methods

        /// <summary>
        ///   Overloaded operator, compares 2 RibbonControlLengths.
        /// </summary>
        public static bool operator ==(RibbonControlLength length1, RibbonControlLength length2)
        {
            return (length1.RibbonControlLengthUnitType == length2.RibbonControlLengthUnitType &&
                length1.Value == length2.Value);
        }

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