HandyOrg/HandyControl · error · NotSupportedException

Specified type ' ' is not supported.

Error message

Specified type '{0}' is not supported.

What it means

PathSegmentHelper.Create attempts to build a PathSegmentImplementation for each known PathSegment subclass (LineSegment, PolyLineSegment, BezierSegment, PolyBezierSegment, QuadraticBezierSegment, PolyQuadraticBezierSegment, ArcSegment). If the supplied segment matches none of them, it throws NotSupportedException with the segment's type name inserted via ExceptionStringTable.TypeNotSupported.

Solutions

1. Only use the built-in WPF segment types (LineSegment, PolyLineSegment, BezierSegment, PolyBezierSegment, QuadraticBezierSegment, PolyQuadraticBezierSegment, ArcSegment).
2. Convert custom segments to an equivalent built-in type before passing to path helpers (e.g. approximate a custom curve with a PolyBezierSegment).
3. Check segment types before calling Create and handle unsupported ones explicitly.
4. Catch NotSupportedException and skip/log the unsupported segment instead of failing the whole path.

Example fix

// before
var impl = PathSegmentHelper.Create(myCustomSegment); // throws NotSupportedException

// after
PathSegment safeSegment = myCustomSegment is LineSegment || myCustomSegment is BezierSegment
    ? myCustomSegment
    : new PolyLineSegment(); // or convert custom segment to a supported type
var impl = PathSegmentHelper.Create(safeSegment);

bool supported = seg is LineSegment || seg is PolyLineSegment || seg is BezierSegment || seg is PolyBezierSegment || seg is QuadraticBezierSegment || seg is PolyQuadraticBezierSegment || seg is ArcSegment;
if (!supported) throw new NotSupportedException($"{seg.GetType().Name} must be converted to a built-in segment.");

static bool IsSupportedSegment(PathSegment s) => s is LineSegment || s is PolyLineSegment || s is BezierSegment || s is PolyBezierSegment || s is QuadraticBezierSegment || s is PolyQuadraticBezierSegment || s is ArcSegment;

try { impl = PathSegmentHelper.Create(segment); }
catch (NotSupportedException ex) { Log.Warn(ex.Message); impl = null; /* skip segment */ }

When it happens

Trigger: Passing a PathSegment that is not one of the seven supported WPF segment types — e.g. a custom PathSegment subclass or a null-derived unknown type — into PathSegmentHelper.Create(segment) or Create(segment, start).

Common situations: Custom geometry code where a user-defined PathSegment subclass was added to a PathGeometry; third-party geometry libraries producing their own segment types; geometry deserialization that produced unexpected segment instances.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

• NotSupportedException
• NotSupportedException
• NotSupportedException
• NotSupportedException
• Can't call EndInit without first calling BeginInit.

AI-assisted analysis of HandyOrg/HandyControl@2c0875ebd6 (2026-09-14). Data as JSON: /api/errors/5633bd4bcc638749. Report an issue: GitHub.

Appendix: source

Thrown at src/Shared/Microsoft.Expression.Drawing/Drawing/PathSegmentHelper.cs:534

        public abstract PathSegment ApplyTransform(GeneralTransform transform);

        public static PathSegmentImplementation Create(PathSegment segment)
        {
            PathSegmentImplementation implementation;
            if ((implementation = BezierSegmentImplementation.Create(segment as BezierSegment)) == null &&
                (implementation = LineSegmentImplementation.Create(segment as LineSegment)) == null &&
                (implementation = ArcSegmentImplementation.Create(segment as ArcSegment)) == null &&
                (implementation = PolyLineSegmentImplementation.Create(segment as PolyLineSegment)) ==
                null &&
                (implementation = PolyBezierSegmentImplementation.Create(segment as PolyBezierSegment)) ==
                null &&
                (implementation =
                    QuadraticBezierSegmentImplementation.Create(segment as QuadraticBezierSegment)) ==
                null &&
                (implementation =
                    PolyQuadraticBezierSegmentImplementation.Create(segment as PolyQuadraticBezierSegment)
                ) == null)
                throw new NotSupportedException(string.Format(CultureInfo.CurrentCulture,
                    ExceptionStringTable.TypeNotSupported, new object[] { segment.GetType().FullName }));
            return implementation;
        }

        public static PathSegmentImplementation Create(PathSegment segment, Point start)
        {
            var implementation = Create(segment);
            implementation.Start = start;
            return implementation;
        }

        public abstract void Flatten(IList<Point> points, double tolerance);

        public abstract Point GetPoint(int index);

        public abstract IEnumerable<SimpleSegment> GetSimpleSegments();
    }

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