stride3d/stride · error · InvalidOperationException

Property Key path parse error: could not parse indexer value

Error message

Property Key path parse error: could not parse indexer value '{indexerName}'

What it means

ParameterCollectionResolver.ResolveIndexer maps an indexer string to a registered ParameterKey via ParameterKeys.FindByName. It throws InvalidOperationException when no parameter key with that name exists, meaning the property path references an unregistered or misspelled key.

Solutions

Verify the exact key name exists (search ParameterKeys registrations) and fix typos in the path.
Ensure the module/assembly that registers the key (static ParameterKeys class) is loaded before resolution.
Update asset/script property paths after renaming a ParameterKey.

Example fix

// before
// indexer 'MyKeys.WrongName' -> FindByName returns null
// after
// indexer 'MyKeys.CorrectName' or register:
public static readonly ParameterKey<bool> CorrectName = ParameterKeys.New("MyKeys.CorrectName");

Defensive patterns

Strategy: validation

Validate before calling

if (ParameterKeys.FindByName(keyName) == null)
    Log.Warning($"ParameterKey '{keyName}' not registered; fix the property path or register the key.");

Try / catch

try { resolver.ResolveIndexer(keyName); }
catch (InvalidOperationException) { Log.Error($"Unknown parameter key '{keyName}' in property path."); }

Prevention

Reference keys via typed constants (ParameterKeys class) instead of raw strings where possible.
Update property paths whenever a ParameterKey is renamed.
Ensure the assembly registering the keys is loaded before resolution.

When it happens

Trigger: Property path indexer string that matches no ParameterKey registered in ParameterKeys (typos, key removed/renamed, key registered in a different module after resolution).

Common situations: Shader/parameter keys renamed in a Stride upgrade, referencing keys from an effect/module that was never loaded, or hand-edited asset property paths.

Understand the failure class

Background: 'Could not be found', 'does not exist', 'not found in database': the resource-not-found family when an ID, slug, key, or URI lookup comes back empty — this error's family across 20 libraries.

Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

AI-assisted analysis of stride3d/stride@96fad776d2 (2026-09-14). Data as JSON: /api/errors/9c1787332bd4dde4. Report an issue: GitHub.

Appendix: source

Thrown at sources/engine/Stride.Engine/Engine/Design/ParameterCollectionResolver.cs:29

namespace Stride.Engine.Design
{
    public class ParameterCollectionResolver : UpdateMemberResolver
    {
        [ModuleInitializer]
        internal static void InitializeModule()
        {
            UpdateEngine.RegisterMemberResolver(new ParameterCollectionResolver());
        }

        public override Type SupportedType => typeof(ParameterCollection);

        [UnconditionalSuppressMessage("Trimming", "IL2076", Justification = "Accessor instantiations rooted by UpdateEngineProcessor (InstantiateValueAccessor<KeyType>).")]
        [UnconditionalSuppressMessage("AOT", "IL3050", Justification = "Accessor instantiation rooted by UpdateEngineProcessor (InstantiateValueAccessor<KeyType>).")]
        public override UpdatableMember ResolveIndexer(string indexerName)
        {
            var key = ParameterKeys.FindByName(indexerName);
            if (key == null)
                throw new InvalidOperationException($"Property Key path parse error: could not parse indexer value '{indexerName}'");

            switch (key.Type)
            {
                case ParameterKeyType.Value:
                    var accessorType = typeof(ValueParameterCollectionAccessor<>).MakeGenericType(key.PropertyType);
                    return (UpdatableMember)Activator.CreateInstance(accessorType, key);
                case ParameterKeyType.Object:
                    return new ObjectParameterCollectionAccessor(key);
                default:
                    throw new NotSupportedException($"{nameof(ParameterCollectionResolver)} can only handle Value and Object keys");
            }
        }

        // Needed for AOT platforms
        public static void InstantiateValueAccessor<T>() where T : struct
        {
            new ValueParameterCollectionAccessor<T>(null);
        }

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