dotnet/wpf · error · ArgumentException

SR.InvalidIsButtonForId

Error message

SR.InvalidIsButtonForId

What it means

The StylusPointProperty.Initialize method (called from the constructor) validates the isButton flag against the well-known Guid table. If the identifier is a known button Guid (e.g. TipButton, BarrelButton) but isButton is false, an ArgumentException naming isButton is thrown, because declaring a known button as a non-button is contradictory.

Solutions

  1. Pass true for Guids that are known buttons (StylusPointPropertyIds.IsKnownButton returns true for them).
  2. Derive the flag automatically: new StylusPointProperty(id, StylusPointPropertyIds.IsKnownButton(id)).
  3. Use the predefined static properties (e.g. StylusPointPropertyIds.TipButton entry in StylusPointProperty) instead of constructing manually.

Example fix

// before
var prop = new StylusPointProperty(StylusPointPropertyIds.TipButton, false);
// after
var prop = new StylusPointProperty(StylusPointPropertyIds.TipButton, true);
Defensive patterns

Strategy: validation

Validate before calling

bool valid = !StylusPointPropertyIds.IsKnownButton(id) || isButton;

Try / catch

try { var p = new StylusPointProperty(id, isButton); }
catch (ArgumentException) { p = new StylusPointProperty(id, !isButton); }

Prevention

When it happens

Trigger: Calling new StylusPointProperty(StylusPointPropertyIds.TipButton /* or another known button Guid */, false).

Common situations: Re-creating standard properties from a Guid table loaded from device data and mislabeling buttons; using a loop over Guids with a hardcoded isButton value; copy-paste code that passes false for all properties.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/8086f82729b5c7eb. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Input/Stylus/Common/StylusPointProperty.cs:55

            Initialize(stylusPointProperty.Id, stylusPointProperty.IsButton);
        }

        /// <summary>
        /// Common ctor helper
        /// </summary>
        /// <param name="identifier">identifier</param>
        /// <param name="isButton">isButton</param>
        private void Initialize(Guid identifier, bool isButton)
        {
            //
            // validate isButton for known guids
            //
            if (StylusPointPropertyIds.IsKnownButton(identifier))
            {
                if (!isButton)
                {
                    //error, this is a known button
                    throw new ArgumentException(SR.InvalidIsButtonForId, nameof(isButton));
                }
            }
            else
            {
                if (StylusPointPropertyIds.IsKnownId(identifier) && isButton)
                {
                    //error, this is a known guid that is NOT a button
                    throw new ArgumentException(SR.InvalidIsButtonForId2, nameof(isButton));
                }
            }

            _id = identifier;
            _isButton = isButton;
        }

        /// <summary>
        /// Id
        /// </summary>

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