dotnet/wpf · error · ArgumentException

InvalidGuid

Error message

InvalidGuid

What it means

Thrown by ExtendedPropertySerializer.Validate when an extended property is registered with Guid.Empty as its identifier. Every extended property must carry a real, unique GUID so ISF can key it; an empty GUID is meaningless and cannot be serialized or matched on load.

Solutions

1. Supply a valid, non-empty Guid when adding the extended property (use Guid.NewGuid() or a fixed application GUID).
2. Check where the GUID originates — fix parsing of the GUID string (Guid.TryParse) so it cannot silently become Guid.Empty.
3. If the property is optional, skip adding it when no valid id is available.

Example fix

// before
stroke.ExtendedProperties.Add(Guid.Empty, 42);
// after
Guid id = Guid.NewGuid(); // or a fixed application-specific GUID
stroke.ExtendedProperties.Add(id, 42);

Guid id = parsedViaTryParse ?? Guid.NewGuid();
if (id == Guid.Empty) throw new ArgumentException("Extended property id must be a non-empty Guid");

bool IsValidPropertyId(Guid id) => id != Guid.Empty;

try { props.Add(id, value); }
catch (ArgumentException ex) when (ex.ParamName == "id") { Log.Error("Extended property id was Guid.Empty", ex); }

When it happens

Trigger: Calling Add on Stroke.ExtendedProperties / DrawingAttributes.ExtendedProperties with an empty Guid as the id, or InvokeValidateAsISF paths that pass Guid.Empty.

Common situations: Building extended property identifiers from parsed config or metadata where the GUID string failed to parse and defaulted to Guid.Empty; copy-paste code that forgot to set the id.

Related errors

• Global Custom Attribute tag embedded in ISF stream does not…
• Drawing Attribute tag embedded in ISF stream does not match…
• GUID cannot be empty.
• InvalidValueType
• InvalidValueType1

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/e7d055a866f08084. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/PresentationCore/MS/internal/Ink/InkSerializedFormat/CustomAttributeSerializer.cs:773

                {
                    guids[count++] = attribute.Id;
                }
            }
            return guids;
        }

        #region Key/Value pair validation helpers
        /// <summary>
        /// Validates the data to be associated with a ExtendedProperty id
        /// </summary>
        /// <param name="id">ExtendedProperty identifier</param>
        /// <param name="value">data</param>
        /// <remarks>Ignores Ids that are not known (e.g. ExtendedProperties)</remarks>
        internal static void Validate(Guid id, object value)
        {
            if (id == Guid.Empty)
            {
                throw new ArgumentException(SR.InvalidGuid);
            }

            if (id == KnownIds.Color)
            {
                if (!(value is System.Windows.Media.Color))
                {
                    throw new ArgumentException(SR.Format(SR.InvalidValueType, typeof(System.Windows.Media.Color)), nameof(value));
                }
            }
                // int attributes
            else if (id == KnownIds.CurveFittingError)
            {
                if (!(value.GetType() == typeof(int)))
                {
                    throw new ArgumentException(SR.Format(SR.InvalidValueType, typeof(int)), nameof(value));
                }
            }
            else if (id == KnownIds.DrawingFlags)

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