Unity-Technologies/UnityCsReference · error · ArgumentNullException

property

Error message

property

What it means

Thrown by ObjectSelector.Show when the SerializedProperty argument is null. The object-selector requires a valid property to read objectReferenceValue and bind the edited target object.

Source

Thrown at Editor/Mono/ObjectSelector.cs:604

        {
            return (String.Equals(typeof(AudioMixerGroup).Name, typeStr));
        }

        internal void Show(Type requiredType, SerializedProperty property, bool allowSceneObjects, List<EntityId> allowedEntityIds = null, Action<UnityObject> onObjectSelectorClosed = null, Action<UnityObject> onObjectSelectedUpdated = null, bool allowBuiltinResources = true, bool excludeSceneAssets = false)
        {
            Show(new [] { requiredType }, property, allowSceneObjects, allowedEntityIds, onObjectSelectorClosed, onObjectSelectedUpdated, allowBuiltinResources, excludeSceneAssets);
        }

        internal void Show(Type[] requiredTypes, SerializedProperty property, bool allowSceneObjects, List<EntityId> allowedEntityIds = null, Action<UnityObject> onObjectSelectorClosed = null, Action<UnityObject> onObjectSelectedUpdated = null, bool allowBuiltinResources = true, bool excludeSceneAssets = false)
        {
            if (requiredTypes == null)
            {
                // Required type list handles null elements if a property exists.
                requiredTypes = new Type [] { null };
            }

            if (property == null)
                throw new ArgumentNullException(nameof(property));

            // Don't select anything on multi selection
            UnityObject obj = property.hasMultipleDifferentValues ? null : property.objectReferenceValue;

            UnityObject objectBeingEdited = property.serializedObject.targetObject;
            m_EditedProperty = property;

            SharedShow(obj, new RequiredTypeList(requiredTypes, property), objectBeingEdited, allowSceneObjects, allowedEntityIds, onObjectSelectorClosed, onObjectSelectedUpdated, true, allowBuiltinResources, excludeSceneAssets);
        }

        internal void Show(UnityObject obj, Type requiredType, UnityObject objectBeingEdited, bool allowSceneObjects, List<EntityId> allowedEntityIds = null, Action<UnityObject> onObjectSelectorClosed = null, Action<UnityObject> onObjectSelectedUpdated = null, bool showNoneItem = true, bool allowBuiltinResources = true, bool excludeSceneAssets = false)
        {
            Show(obj, new Type[] { requiredType }, objectBeingEdited, allowSceneObjects, allowedEntityIds, onObjectSelectorClosed, onObjectSelectedUpdated, showNoneItem, allowBuiltinResources, excludeSceneAssets);
        }

        internal void Show(UnityObject obj, Type[] requiredTypes, UnityObject objectBeingEdited, bool allowSceneObjects, List<EntityId> allowedEntityIds = null, Action<UnityObject> onObjectSelectorClosed = null, Action<UnityObject> onObjectSelectedUpdated = null, bool showNoneItem = true, bool allowBuiltinResources = true, bool excludeSceneAssets = false)
        {
            SharedShow(

View on GitHub (pinned to 225b0fbdb5)

Solutions

1. Verify the property path: serializedObject.FindProperty("path") != null before calling Show.
2. Refresh the SerializedObject before property lookups.
3. Use the obj-based Show overload if you have a direct UnityObject reference instead.

Example fix

// before
var prop = so.FindProperty("maybeMissing");
ObjectSelector.get.Show(new[]{ typeof(Material) }, prop, ...);
// after
var prop = so.FindProperty("maybeMissing");
if (prop == null) { Debug.LogError("property missing"); return; }
ObjectSelector.get.Show(new[]{ typeof(Material) }, prop, ...);

var prop = so.FindProperty("path");
if (prop != null) ObjectSelector.get.Show(types, prop, ...);

When it happens

Trigger: Calling ObjectSelector.Show(...) with property == null after the requiredTypes null-default branch.

Common situations: SerializedProperty lookup returned null because the property path was wrong or the serializedObject changed; editor code invoking the selector without checking the property exists.

Related errors

• Cannot add dependency on invalid ArtifactKey.
• The object to add cannot be null.
• The object to remove cannot be null.
• Platform GUID {platformGuid} is not a valid Unity build plat
• rendererIDs and results NativeArrays don't match in length.

AI-assisted analysis of Unity-Technologies/UnityCsReference@225b0fbdb5 (2026-08-13). Data as JSON: /api/errors/e6082b6feff6a008. Report an issue: GitHub.