dotnet/wpf · error · InvalidEnumArgumentException

SR.Format(SR.Enum_Invalid, nameof(actions))

Error message

SR.Format(SR.Enum_Invalid, nameof(actions))

What it means

This RawStylusInputReport constructor validates that the RawStylusActions value is a defined/valid combination via RawStylusActionsHelper.IsValid. An undefined enum value throws InvalidEnumArgumentException with SR.Enum_Invalid.

Solutions

  1. Pass only defined RawStylusActions values (Down, Move, Up, InRange, InAirMove, etc.) or valid combinations
  2. Validate with RawStylusActionsHelper.IsValid(actions) (or Enum.IsDefined on your own flags) before constructing
  3. Audit casts of raw integers to RawStylusActions

Example fix

// before
var report = new RawStylusInputReport(mode, ts, inputSource, (RawStylusActions)rawInt, penContext, tabletId, stylusId, data);
// after
var actions = (RawStylusActions)rawInt;
if (!RawStylusActionsHelper.IsValid(actions)) throw new ArgumentException(nameof(actions));
var report = new RawStylusInputReport(mode, ts, inputSource, actions, penContext, tabletId, stylusId, data);
Defensive patterns

Strategy: validation

Validate before calling

if (!RawStylusActionsHelper.IsValid(actions)) throw new ArgumentException(nameof(actions));

Try / catch

try { new RawStylusInputReport(...); } catch (InvalidEnumArgumentException) { /* sanitize enum value */ }

Prevention

When it happens

Trigger: Constructing a RawStylusInputReport (PenContext overload) passing an actions value that is not a valid RawStylusActions bitmask, such as a cast from an arbitrary int (e.g. (RawStylusActions)999).

Common situations: Custom pen/stylus test harnesses or interop code fabricating input reports with hand-picked integer action values; deserializing persisted reports where the enum value came from a different framework version.

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/0b9af9d8efb47452. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Input/Stylus/Common/RawStylusInputReport.cs:181

        /// </param>
        /// <param name="data">
        ///     Raw stylus data.
        /// </param>
        internal RawStylusInputReport(
            InputMode mode,
            int timestamp,
            PresentationSource inputSource,
            PenContext penContext,
            RawStylusActions actions,
            int tabletDeviceId,
            int stylusDeviceId,
            int[] data)
            : this(mode, timestamp, inputSource, actions, () => { return penContext.StylusPointDescription; }, tabletDeviceId, stylusDeviceId, data)
        {
            // Validate parameters
            if (!RawStylusActionsHelper.IsValid(actions))
            {
                throw new InvalidEnumArgumentException(SR.Format(SR.Enum_Invalid, nameof(actions)));
            }
            if (actions != RawStylusActions.InRange)
            {
                ArgumentNullException.ThrowIfNull(data);
            }

            _actions = actions;
            _data = data;
            _isSynchronize = false;
            _tabletDeviceId = tabletDeviceId;
            _stylusDeviceId = stylusDeviceId;
            PenContext = penContext;
        }

        /// <summary>
        ///     Constructs an instance of the RawStylusInputReport class.
        /// </summary>
        /// <param name="mode">

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