stride3d/stride · error · InvalidOperationException

This item is not a Member

Error message

This item is not a Member

What it means

YamlAssetPath.Element is a tagged union: its Value meaning depends on Type (Member name string, Index int, ItemId Guid). AsMember() casts Value to string and throws InvalidOperationException if the element's Type is not ElementType.Member.

Solutions

1. Check item.Type == ElementType.Member before calling AsMember()
2. Use switch/if on ElementType to dispatch to AsMember/AsItemId/Index appropriately
3. Fix the code that built the YamlAssetPath so member elements are pushed with PushMember
4. Log the element Type to find where the wrong element was appended

Example fix

// before
string name = element.AsMember();
// after
string name = element.Type == YamlAssetPath.ElementType.Member
    ? element.AsMember()
    : throw new InvalidOperationException($"Unexpected element type {element.Type}");

if (element.Type != YamlAssetPath.ElementType.Member)
    throw new InvalidOperationException($"Element is {element.Type}, expected Member");

bool TryAsMember(in YamlAssetPath.Element e, out string name)
{ name = e.Type == YamlAssetPath.ElementType.Member ? e.AsMember() : null; return name is not null; }

try { name = element.AsMember(); }
catch (InvalidOperationException ex) { logger.Error(ex, "Path element is not a member"); continue; }

When it happens

Trigger: Calling AsMember() on a path element whose ElementType is Index or ItemId — e.g. iterating path elements and assuming all are members when a path also contains collection indices or item ids.

Common situations: Editor/plugin code walking YamlAssetPath elements to build UI breadcrumbs or fixups; scripts mis-parsing paths produced for list items or dictionary entries; off-by-one in path construction so a member call lands on an index element.

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

• This item is not a item Id
• Unable to extract url reference from object
• The given container does not match the expected type.
• The given container does not match the expected type.
• The path [ ] contains access to a member of a null object.

AI-assisted analysis of stride3d/stride@96fad776d2 (2026-09-14). Data as JSON: /api/errors/6e1031459dfa4265. Report an issue: GitHub.

Appendix: source

Thrown at sources/assets/Stride.Core.Assets/Yaml/YamlAssetPath.cs:68

        /// <summary>
        /// Initializes a new instance of the <see cref="Element"/> structure.
        /// </summary>
        /// <param name="type">The type of element.</param>
        /// <param name="value">The value of the element.</param>
        public Element(ElementType type, object value)
        {
            Type = type;
            Value = value;
        }

        /// <summary>
        /// Fetches the name of the member, considering this element is a <see cref="ElementType.Member"/>.
        /// </summary>
        /// <returns>The name of the member.</returns>
        public readonly string AsMember()
        {
            if (Type != ElementType.Member) throw new InvalidOperationException("This item is not a Member");
            return (string)Value;
        }

        /// <summary>
        /// Returns the <see cref="ItemId"/> of this element, considering this element is a <see cref="ElementType.ItemId"/>.
        /// </summary>
        /// <returns>The <see cref="ItemId"/> of the item.</returns>
        public readonly ItemId AsItemId()
        {
            if (Type != ElementType.ItemId) throw new InvalidOperationException("This item is not a item Id");
            return (ItemId)Value;
        }

        /// <inheritdoc/>
        public readonly bool Equals(Element other)
        {
            return Type == other.Type && Equals(Value, other.Value);
        }

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