HandyOrg/HandyControl · error · InvalidOperationException

Animation_NoTextChildren

Error message

Animation_NoTextChildren

What it means

GeometryAnimationUsingKeyFrames.AddText throws InvalidOperationException("Animation_NoTextChildren") because a key-frame geometry animation cannot be built from raw text content. XAML content between its tags must be GeometryKeyFrame elements; any literal text (including stray whitespace-formatted text nodes) reaches AddText and is rejected.

Solutions

1. Remove all text content from the GeometryAnimationUsingKeyFrames element in XAML; only GeometryKeyFrame child elements are allowed.
2. Replace inline text with proper <GeometryKeyFrame Value="..." /> elements.
3. Validate the XAML compiles and inspect the element for stray characters between tags.

Example fix

// before
<GeometryAnimationUsingKeyFrames>
    M0,0 L100,100 <!-- invalid text child -->
</GeometryAnimationUsingKeyFrames>
// after
<GeometryAnimationUsingKeyFrames>
    <GeometryKeyFrame Value="M0,0 L100,100" KeyTime="0:0:1" />
</GeometryAnimationUsingKeyFrames>

try { animation.AddText(text); } catch (InvalidOperationException ex) when (ex.Message == "Animation_NoTextChildren") { // text is not a valid child; convert to GeometryKeyFrame or discard
}

When it happens

Trigger: Putting literal text or an unrecognized string inside <GeometryAnimationUsingKeyFrames>...</GeometryAnimationUsingKeyFrames> in XAML, causing IAddChild.AddText to be invoked.

Common situations: Typing a comment or stray characters inside the animation element; using inner text from a template meant for GeometryAnimation; malformed XAML where a child collapsed into text.

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

• Animation_ChildMustBeKeyFrame
• CannotConvertType
• The dialog is not a derived class of the FrameworkElement.
• Calls to BeginInit cannot be nested.
• The JumpList can't be applied until EndInit has been called.

AI-assisted analysis of HandyOrg/HandyControl@2c0875ebd6 (2026-09-14). Data as JSON: /api/errors/2b6d662334781d8d. Report an issue: GitHub.

Appendix: source

Thrown at src/Shared/HandyControl_Shared/Media/Animation/GeometryAnimationUsingKeyFrames.cs:166

        }
        else
        {
            throw new ArgumentException("Animation_ChildMustBeKeyFrame", nameof(child));
        }
    }

    void IAddChild.AddText(string childText)
    {
        if (childText == null)
        {
            throw new ArgumentNullException(nameof(childText));
        }

        AddText(childText);
    }

    [EditorBrowsable(EditorBrowsableState.Advanced)]
    protected virtual void AddText(string childText) => throw new InvalidOperationException("Animation_NoTextChildren");

    protected override Geometry GetCurrentValueCore(Geometry defaultOriginValue, Geometry defaultDestinationValue, AnimationClock animationClock)
    {
        if (_keyFrames == null)
        {
            return defaultDestinationValue;
        }

        if (!_areKeyTimesValid)
        {
            ResolveKeyTimes();
        }

        if (_sortedResolvedKeyFrames == null)
        {
            return defaultDestinationValue;
        }

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