What causes "SR.Animation_Invalid_DefaultValue" in dotnet/wpf?

Initialize the animated property to a valid, non-empty Rect (e.g. new Rect(0,0,100,100)) before the animation runs

dotnet/wpf · error · InvalidOperationException

SR.Animation_Invalid_DefaultValue

Error message

SR.Animation_Invalid_DefaultValue

What it means

RectAnimation.GetCurrentValueCore throws this InvalidOperationException when the default origin value supplied by the animation system is not a valid animation value for type Rect (checked via AnimatedTypeHelpers.IsValidAnimationValueRect). WPF requires origin/destination fallback values to be valid, finite Rect values; an invalid (e.g. empty or non-animatable) value cannot seed the interpolation. The message names the offending property ('origin') and its value.

Solutions

Initialize the animated property to a valid, non-empty Rect (e.g. new Rect(0,0,100,100)) before the animation runs
Provide explicit From/To values on the RectAnimation so default origin/destination values are not needed
Wrap the animation start in try/catch for InvalidOperationException and fall back to a valid base value

Example fix

// before
rectAnimation.From = null; // relies on base value which is Rect.Empty
// after
rectAnimation.From = new Rect(0, 0, 100, 100); // valid origin, no default needed

Defensive patterns

Strategy: validation

Validate before calling

if (!rect.IsValid || rect == Rect.Empty) { /* fix or set a valid base value before animating */ }

Type guard

bool IsValidAnimationOrigin(Rect r) => r != Rect.Empty && r.Width >= 0 && r.Height >= 0;

Try / catch

try { target.BeginAnimation(RectProperty, anim); } catch (InvalidOperationException ex) when (ex.Message.Contains("origin")) { anim.From = new Rect(0,0,1,1); target.BeginAnimation(RectProperty, anim); }

Prevention

Always initialize Rect-typed properties to a non-empty Rect before animating
Prefer explicit From/To on animations over relying on base values
Check Rect.IsEmpty before BeginAnimation

When it happens

Trigger: Calling GetCurrentValueCore (directly or via the animation clock) with validateOrigin=true and a defaultOriginValue that fails AnimatedTypeHelpers.IsValidAnimationValueRect — e.g. Rect.Empty or an uninitialized Rect used as the base value of the animated property.

Common situations: Animating a Rect-typed dependency property whose current value is Rect.Empty (e.g. RectangleGeometry.Rect never initialized), or hand-rolled animation code passing an empty/default Rect as the origin.

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/d0e74b103aa06a0d. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media/Animation/Generated/RectAnimation.cs:313

                    if (IsAdditive)
                    {
                        foundation = defaultOriginValue;
                        validateOrigin = true;
                    }

                    break;

                default:

                    Debug.Fail("Unknown animation type.");

                    break;
            }

            if (validateOrigin 
                && !AnimatedTypeHelpers.IsValidAnimationValueRect(defaultOriginValue))
            {
                throw new InvalidOperationException(
                    SR.Format(
                        SR.Animation_Invalid_DefaultValue,
                        this.GetType(),
                        "origin",
                        defaultOriginValue.ToString(CultureInfo.InvariantCulture)));
            }

            if (validateDestination 
                && !AnimatedTypeHelpers.IsValidAnimationValueRect(defaultDestinationValue))
            {
                throw new InvalidOperationException(
                    SR.Format(
                        SR.Animation_Invalid_DefaultValue,
                        this.GetType(),
                        "destination",
                        defaultDestinationValue.ToString(CultureInfo.InvariantCulture)));
            }

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