dotnet/wpf · error · ArgumentOutOfRangeException

Specified argument was out of range of valid values…

Error message

Specified argument was out of range of valid values. (Parameter 'value')

What it means

The PageTrueTypeFont mode setting setter validates the assigned value against PrintSchema.TrueTypeFontModeEnumMin..Max. Assigning an int outside the defined TrueTypeFontMode enum range throws ArgumentOutOfRangeException with parameter 'value'.

Solutions

  1. Ensure the assigned value is a valid TrueTypeFontMode enum member
  2. Validate raw ints from external sources against Enum.IsDefined before casting
  3. Catch ArgumentOutOfRangeException and fall back to DeviceFont or Automatic default

Example fix

// before
mode = (TrueTypeFontMode)rawInt;
ticket.PageTrueTypeFont.Mode = mode;
// after
if (Enum.IsDefined(typeof(TrueTypeFontMode), rawInt))
    ticket.PageTrueTypeFont.Mode = (TrueTypeFontMode)rawInt;
Defensive patterns

Strategy: validation

Validate before calling

bool IsValidTrueTypeFontMode(int v) => v >= PrintSchema.TrueTypeFontModeEnumMin && v <= PrintSchema.TrueTypeFontModeEnumMax;

Type guard

static bool IsDefinedTrueTypeFontMode(object v) => v is int i && i >= PrintSchema.TrueTypeFontModeEnumMin && i <= PrintSchema.TrueTypeFontModeEnumMax;

Try / catch

try { ticket.PageTrueTypeFont.Mode = (TrueTypeFontMode)value; }
catch (ArgumentOutOfRangeException) { ticket.PageTrueTypeFont.Mode = TrueTypeFontMode.Automatic; }

Prevention

When it happens

Trigger: Assigning printTicket.PageTrueTypeFont.Mode (or the underlying PageTrueTypeFontModeSetting.Value) with a raw int not in the TrueTypeFontMode enum, e.g. from persisted data or an unvalidated cast.

Common situations: Loading saved PrintTicket XML from a different runtime version; round-tripping enum values through string/int config stores.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/5c281db1c290a847. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/ReachFramework/PrintConfig/PageTrueTypeFont.cs:254

        /// </summary>
        /// <remarks>
        /// If the setting is not specified yet, getter will return 0.
        /// </remarks>
        /// <exception cref="ArgumentOutOfRangeException">
        /// The value to set is not one of the standard <see cref="TrueTypeFontMode"/>.
        /// </exception>
        public TrueTypeFontMode Value
        {
            get
            {
                return (TrueTypeFontMode)this[PrintSchemaTags.Framework.OptionNameProperty];
            }
            set
            {
                if (value < PrintSchema.TrueTypeFontModeEnumMin ||
                    value > PrintSchema.TrueTypeFontModeEnumMax)
                {
                    throw new ArgumentOutOfRangeException(nameof(value));
                }

                this[PrintSchemaTags.Framework.OptionNameProperty] = (int)value;
            }
        }

        #endregion Public Properties

        #region Public Methods

        /// <summary>
        /// Converts the page TrueType font handling mode setting to human-readable string.
        /// </summary>
        /// <returns>A string that represents this page TrueType font handling mode setting.</returns>
        public override string ToString()
        {
            return Value.ToString();
        }

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