stride3d/stride · error · ArgumentNullException

Value cannot be null. (Parameter 'element')

Error message

Value cannot be null. (Parameter 'element')

What it means

Argument-null validation in RendererManager.RegisterRenderer (invoked via RegisterRendererFactory's registration path): the element parameter is null. The renderer registration needs the concrete UIElement instance to associate with the created renderer; a null element cannot be keyed in elementIdToRenderer, so the call is rejected with ArgumentNullException named 'element'.

Solutions

1. Pass a fully constructed, non-null UIElement instance to RegisterRenderer.
2. Check the element for null at the call site (e.g. when it comes from a lookup, hit-test or factory that can return null) before registering its renderer.
3. Delay registration until the element has actually been created rather than registering a placeholder null.

When it happens

Trigger: Thrown at sources/engine/Stride.UI/Renderers/RendererManager.cs:75 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of stride3d/stride@96fad776d2 (2026-09-14). Data as JSON: /api/errors/28f9afba5549f946. Report an issue: GitHub.

Appendix: source

Thrown at sources/engine/Stride.UI/Renderers/RendererManager.cs:75

            }

            return elementRenderer;
        }

        public void RegisterRendererFactory(Type uiElementType, IElementRendererFactory factory)
        {
            if (uiElementType == null) throw new ArgumentNullException(nameof(uiElementType));
            if (factory == null) throw new ArgumentNullException(nameof(factory));

            if (!typeof(UIElement).GetTypeInfo().IsAssignableFrom(uiElementType.GetTypeInfo()))
                throw new InvalidOperationException(uiElementType + " is not a descendant of UIElement.");

            typesToUserFactories[uiElementType] = factory;
        }

        public void RegisterRenderer(UIElement element, ElementRenderer renderer)
        {
            if (element == null) throw new ArgumentNullException(nameof(element));
            if (renderer == null) throw new ArgumentNullException(nameof(renderer));

            elementIdToRenderer[element.Id] = renderer;
        }

        public void Dispose()
        {
            foreach (var renderer in elementIdToRenderer.Values)
            {
                if (!renderer.IsDisposed)
                    renderer.Dispose();
            }
            elementIdToRenderer.Clear();
        }
    }
}

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