Data model paths - Added support for lists

Data model paths - Added deferred compilation to accessors
Data models - Fixed property name being empty sometimes
Plugins - Fixed disabling plugins that failed to load

src/Artemis.Core/Models/Profile/DataModel/DataModelPath.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.Collections.ObjectModel;
 using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
@@ -13,16 +14,17 @@ namespace Artemis.Core
     /// </summary>
     public class DataModelPath
     {
+        private Expression<Func<object, object>> _accessorLambda;
         private readonly LinkedList<DataModelPathSegment> _segments;
 
         /// <summary>
         ///     Creates a new instance of the <see cref="DataModelPath" /> class
         /// </summary>
-        /// <param name="dataModel">The data model at which this path starts</param>
+        /// <param name="target">The target at which this path starts</param>
         /// <param name="path">A string representation of the <see cref="DataModelPath" /></param>
-        public DataModelPath(object dataModel, string path)
+        public DataModelPath(object target, string path)
         {
-            Target = dataModel ?? throw new ArgumentNullException(nameof(dataModel));
+            Target = target ?? throw new ArgumentNullException(nameof(target));
             Path = path ?? throw new ArgumentNullException(nameof(path));
 
             if (string.IsNullOrWhiteSpace(Path))
@@ -53,34 +55,25 @@ namespace Artemis.Core
         public IReadOnlyCollection<DataModelPathSegment> Segments => _segments.ToList().AsReadOnly();
 
         /// <summary>
-        ///     Gets a boolean indicating whether this data model path can have an inner path because it points to a list
+        ///     Gets a boolean indicating whether this data model path points to a list
         /// </summary>
-        public bool CanHaveInnerPath => Segments.LastOrDefault()?.GetPropertyType()?.IsAssignableFrom(typeof(IList)) ?? false;
+        public bool PointsToList => Segments.LastOrDefault()?.GetPropertyType() != null &&
-
+                                    typeof(IList).IsAssignableFrom(Segments.LastOrDefault()?.GetPropertyType());
-        /// <summary>
-        ///     Gets the inner path of this path, only available if this path points to a list
-        /// </summary>
-        public DataModelPath InnerPath { get; internal set; }
 
         internal Func<object, object> Accessor { get; private set; }
 
-        public void SetInnerPath(string path)
-        {
-            if (!CanHaveInnerPath)
-            {
-                var type = Segments.LastOrDefault()?.GetPropertyType();
-                throw new ArtemisCoreException($"Cannot set an inner path on a data model path if it does not point to a list (value is of type: {type?.Name})");
-            }
-
-            InnerPath = new DataModelPath(GetValue(), path);
-        }
-
         /// <summary>
         ///     Gets the current value of the path
         /// </summary>
         public object GetValue()
         {
-            return Accessor?.Invoke(Target);
+            if (_accessorLambda == null)
+                return null;
+
+            // If the accessor has not yet been compiled do it now that it's first required
+            if (Accessor == null)
+                Accessor = _accessorLambda.Compile();
+            return Accessor(Target);
         }
 
         /// <summary>
@@ -89,8 +82,6 @@ namespace Artemis.Core
         /// <returns>If static, the property info. If dynamic, <c>null</c></returns>
         public PropertyInfo GetPropertyInfo()
         {
-            if (InnerPath != null)
-                return InnerPath.GetPropertyInfo();
             return Segments.LastOrDefault()?.GetPropertyInfo();
         }
 
@@ -100,8 +91,6 @@ namespace Artemis.Core
         /// <returns>If possible, the property type</returns>
         public Type GetPropertyType()
         {
-            if (InnerPath != null)
-                return InnerPath.GetPropertyType();
             return Segments.LastOrDefault()?.GetPropertyType();
         }
 
@@ -111,21 +100,20 @@ namespace Artemis.Core
         /// <returns>If found, the data model property description</returns>
         public DataModelPropertyAttribute GetPropertyDescription()
         {
-            if (InnerPath != null)
-                return InnerPath.GetPropertyDescription();
             return Segments.LastOrDefault()?.GetPropertyDescription();
         }
 
         /// <inheritdoc />
         public override string ToString()
         {
-            if (InnerPath != null)
-                return $"{Path} > {InnerPath}";
             return Path;
         }
 
         private void Initialize(string path)
         {
+            var startSegment = new DataModelPathSegment(this, "target", "target");
+            startSegment.Node = _segments.AddFirst(startSegment);
+
             var segments = path.Split(".");
             for (var index = 0; index < segments.Length; index++)
             {
@@ -147,7 +135,7 @@ namespace Artemis.Core
                     return;
             }
 
-            Accessor = Expression.Lambda<Func<object, object>>(
+            _accessorLambda = Expression.Lambda<Func<object, object>>(
                 // Wrap with a null check
                 Expression.Condition(
                     nullCondition,
@@ -155,7 +143,8 @@ namespace Artemis.Core
                     Expression.Convert(Expression.Default(expression.Type), typeof(object))
                 ),
                 parameter
-            ).Compile();
+            );
+            Accessor = null;
         }
     }
 }

src/Artemis.Core/Models/Profile/DataModel/DataModelPathSegment.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Artemis.Core.DataModelExpansions;
@@ -12,11 +13,14 @@ namespace Artemis.Core
     /// </summary>
     public class DataModelPathSegment
     {
+        private Expression<Func<object, object>> _accessorLambda;
+
         internal DataModelPathSegment(DataModelPath dataModelPath, string identifier, string path)
         {
             DataModelPath = dataModelPath;
             Identifier = identifier;
             Path = path;
+            IsStartSegment = !DataModelPath.Segments.Any();
         }
 
         /// <summary>
@@ -34,6 +38,11 @@ namespace Artemis.Core
         /// </summary>
         public string Path { get; }
 
+        /// <summary>
+        ///     Gets a boolean indicating whether this is the first segment in the path
+        /// </summary>
+        public bool IsStartSegment { get; }
+
         /// <summary>
         ///     Gets the type of data model this segment of the path points to
         /// </summary>
@@ -64,7 +73,13 @@ namespace Artemis.Core
         /// <returns></returns>
         public object GetValue()
         {
-            return Type == DataModelPathSegmentType.Invalid ? null : Accessor(DataModelPath.Target);
+            if (Type == DataModelPathSegmentType.Invalid || _accessorLambda == null)
+                return null;
+
+            // If the accessor has not yet been compiled do it now that it's first required
+            if (Accessor == null)
+                Accessor = _accessorLambda.Compile();
+            return Accessor(DataModelPath.Target);
         }
 
         /// <inheritdoc />
@@ -82,12 +97,12 @@ namespace Artemis.Core
             // Dynamic types have no property and therefore no property info
             if (Type == DataModelPathSegmentType.Dynamic)
                 return null;
+            // The start segment has none either because it is the datamodel
+            if (IsStartSegment)
+                return null;
 
-            // If this is the first segment in a path, the property is located on the data model
-            if (Previous == null)
-                return DataModelPath.Target.GetType().GetProperty(Identifier);
             // If this is not the first segment in a path, the property is located on the previous segment
-            return Previous.GetValue()?.GetType().GetProperty(Identifier);
+            return Previous.GetPropertyType()?.GetProperty(Identifier);
         }
 
         /// <summary>
@@ -99,14 +114,24 @@ namespace Artemis.Core
             // Dynamic types have a data model description
             if (Type == DataModelPathSegmentType.Dynamic)
                 return ((DataModel) GetValue())?.DataModelDescription;
+            if (IsStartSegment && DataModelPath.Target is DataModel targetDataModel)
+                return targetDataModel.DataModelDescription;
+            if (IsStartSegment)
+                return null;
 
             var propertyInfo = GetPropertyInfo();
             if (propertyInfo == null)
                 return null;
 
             // Static types may have one as an attribute
-            return (DataModelPropertyAttribute) Attribute.GetCustomAttribute(propertyInfo, typeof(DataModelPropertyAttribute)) ??
+            var attribute = (DataModelPropertyAttribute) Attribute.GetCustomAttribute(propertyInfo, typeof(DataModelPropertyAttribute));
-                   new DataModelPropertyAttribute {Name = propertyInfo.Name.Humanize(), ResetsDepth = false};
+            if (attribute != null)
+            {
+                if (string.IsNullOrWhiteSpace(attribute.Name))
+                    attribute.Name = propertyInfo.Name.Humanize();
+                return attribute;
+            }
+            return new DataModelPropertyAttribute {Name = propertyInfo.Name.Humanize(), ResetsDepth = false};
         }
 
         /// <summary>
@@ -115,6 +140,10 @@ namespace Artemis.Core
         /// <returns>If possible, the property type</returns>
         public Type GetPropertyType()
         {
+            // The start segment type is always the target type
+            if (IsStartSegment)
+                return DataModelPath.Target.GetType();
+
             // Prefer basing the type on the property info
             var propertyInfo = GetPropertyInfo();
             var type = propertyInfo?.PropertyType;
@@ -131,27 +160,35 @@ namespace Artemis.Core
 
         internal Expression Initialize(ParameterExpression parameter, Expression expression, Expression nullCondition)
         {
-            var previousValue = Previous != null ? Previous.GetValue() : DataModelPath.Target;
+            if (IsStartSegment)
-            if (previousValue == null)
             {
-                Type = DataModelPathSegmentType.Invalid;
+                Type = DataModelPathSegmentType.Static;
-                return null;
+                return CreateExpression(parameter, expression, nullCondition);
             }
 
-            // Determine this segment's type by looking for a dynamic data model with the identifier
+            var previousType = Previous.GetPropertyType();
-            if (previousValue is DataModel dataModel)
+            if (previousType == null)
             {
-                var hasDynamicDataModel = dataModel.DynamicDataModels.TryGetValue(Identifier, out var dynamicDataModel);
+                Type = DataModelPathSegmentType.Invalid;
+                return CreateExpression(parameter, expression, nullCondition);
+            }
+
+            // Prefer static since that's faster
+            DetermineStaticType(previousType);
+
+            // If no static type could be found, check if this is a data model and if so, look for a dynamic type
+            if (Type == DataModelPathSegmentType.Invalid && typeof(DataModel).IsAssignableFrom(previousType))
+            {
+                var dataModel = (DataModel) Previous.GetValue();
+                // Cannot determine a dynamic type on a null data model, leave the segment invalid
+                if (dataModel == null)
+                    return CreateExpression(parameter, expression, nullCondition);
+
                 // If a dynamic data model is found the use that
+                var hasDynamicDataModel = dataModel.DynamicDataModels.TryGetValue(Identifier, out var dynamicDataModel);
                 if (hasDynamicDataModel)
                     DetermineDynamicType(dynamicDataModel);
-                // Otherwise look for a static type
-                else
-                    DetermineStaticType(previousValue);
             }
-            // Only data models can have dynamic types so if it is something else, its always going to be static
-            else
-                DetermineStaticType(previousValue);
 
             return CreateExpression(parameter, expression, nullCondition);
         }
@@ -160,13 +197,17 @@ namespace Artemis.Core
         {
             if (Type == DataModelPathSegmentType.Invalid)
             {
+                _accessorLambda = null;
                 Accessor = null;
                 return null;
             }
 
             Expression accessorExpression;
+            // A start segment just accesses the target
+            if (IsStartSegment)
+                accessorExpression = expression;
             // A static segment just needs to access the property or filed
-            if (Type == DataModelPathSegmentType.Static)
+            else if (Type == DataModelPathSegmentType.Static)
                 accessorExpression = Expression.PropertyOrField(expression, Identifier);
             // A dynamic segment calls the generic method DataModel.DynamicChild<T> and provides the identifier as an argument
             else
@@ -179,7 +220,7 @@ namespace Artemis.Core
                 );
             }
 
-            Accessor = Expression.Lambda<Func<object, object>>(
+            _accessorLambda = Expression.Lambda<Func<object, object>>(
                 // Wrap with a null check
                 Expression.Condition(
                     nullCondition,
@@ -187,8 +228,8 @@ namespace Artemis.Core
                     Expression.Convert(Expression.Default(accessorExpression.Type), typeof(object))
                 ),
                 parameter
-            ).Compile();
+            );
-
+            Accessor = null;
             return accessorExpression;
         }
 
@@ -198,9 +239,8 @@ namespace Artemis.Core
             DynamicDataModelType = dynamicDataModel.GetType();
         }
 
-        private void DetermineStaticType(object previous)
+        private void DetermineStaticType(Type previousType)
         {
-            var previousType = previous.GetType();
             var property = previousType.GetProperty(Identifier, BindingFlags.Public | BindingFlags.Instance);
             Type = property == null ? DataModelPathSegmentType.Invalid : DataModelPathSegmentType.Static;
         }

src/Artemis.Core/Plugins/DataModelExpansions/DataModel.cs

@@ -64,7 +64,8 @@ namespace Artemis.Core.DataModelExpansions
                 throw new ArgumentNullException(nameof(dynamicDataModel));
             if (key == null)
                 throw new ArgumentNullException(nameof(key));
-
+            if (key.Contains('.'))
+                throw new ArtemisCoreException("The provided key contains an illegal character (.)");
             if (_dynamicDataModels.ContainsKey(key))
             {
                 throw new ArtemisCoreException($"Cannot add a dynamic data model with key '{key}' " +
@@ -87,7 +88,7 @@ namespace Artemis.Core.DataModelExpansions
             dynamicDataModel.PluginInfo = PluginInfo;
             dynamicDataModel.DataModelDescription = new DataModelPropertyAttribute
             {
-                Name = name ?? key.Humanize(),
+                Name = string.IsNullOrWhiteSpace(name) ? key.Humanize() : name,
                 Description = description
             };
             _dynamicDataModels.Add(key, dynamicDataModel);

src/Artemis.Core/Plugins/Plugin.cs

@@ -105,6 +105,12 @@ namespace Artemis.Core
                 InternalDisablePlugin();
                 OnPluginDisabled();
             }
+            // A failed load is still enabled in plugin info (to avoid disabling it permanently after a fail)
+            // update even that when manually disabling
+            else if (!enable && !Enabled)
+            {
+                PluginInfo.Enabled = false;
+            }
         }
 
         internal virtual void InternalEnablePlugin()

src/Artemis.UI.Shared/DataModelVisualization/Shared/DataModelListPropertiesViewModel.cs

@@ -1,5 +1,4 @@
 using System;
-using Artemis.Core;
 using Artemis.Core.DataModelExpansions;
 using Artemis.UI.Shared.Services;
 
@@ -11,8 +10,11 @@ namespace Artemis.UI.Shared
         private int _index;
         private Type _listType;
 
-        public DataModelListPropertiesViewModel(DataModel dataModel, DataModelVisualizationViewModel parent, DataModelPath dataModelPath) : base(dataModel, parent, dataModelPath)
+        public DataModelListPropertiesViewModel(DataModel dataModel, object listItem) : base(null, null, null)
         {
+            DataModel = dataModel;
+            ListType = listItem.GetType();
+            DisplayValue = listItem;
         }
 
         public int Index
@@ -42,7 +44,7 @@ namespace Artemis.UI.Shared
                 return;
 
             ListType = DisplayValue.GetType();
-            PopulateProperties(dataModelUIService);
+            PopulateProperties(dataModelUIService, DisplayValue);
             foreach (var dataModelVisualizationViewModel in Children)
                 dataModelVisualizationViewModel.Update(dataModelUIService);
         }
@@ -51,5 +53,11 @@ namespace Artemis.UI.Shared
         {
             return DisplayValue;
         }
+
+        /// <inheritdoc />
+        public override string ToString()
+        {
+            return $"[List item {Index}] {DisplayPath ?? Path}";
+        }
     }
 }

src/Artemis.UI.Shared/DataModelVisualization/Shared/DataModelListPropertyViewModel.cs

@@ -1,5 +1,4 @@
 using System;
-using Artemis.Core;
 using Artemis.Core.DataModelExpansions;
 using Artemis.UI.Shared.Services;
 
@@ -10,8 +9,19 @@ namespace Artemis.UI.Shared
         private int _index;
         private Type _listType;
 
-        public DataModelListPropertyViewModel(DataModel dataModel, DataModelVisualizationViewModel parent, DataModelPath dataModelPath) : base(dataModel, parent, dataModelPath)
+        public DataModelListPropertyViewModel(DataModel dataModel, object listItem, DataModelDisplayViewModel displayViewModel) : base(null, null, null)
         {
+            DataModel = dataModel;
+            ListType = listItem.GetType();
+            DisplayValue = listItem;
+            DisplayViewModel = displayViewModel;
+        }
+
+        public DataModelListPropertyViewModel(DataModel dataModel, object listItem) : base(null, null, null)
+        {
+            DataModel = dataModel;
+            ListType = listItem.GetType();
+            DisplayValue = listItem;
         }
 
         public int Index
@@ -43,5 +53,11 @@ namespace Artemis.UI.Shared
             ListType = DisplayValue.GetType();
             UpdateDisplayParameters();
         }
+
+        /// <inheritdoc />
+        public override string ToString()
+        {
+            return $"[List item {Index}] {DisplayPath ?? Path} - {DisplayValue}";
+        }
     }
 }

src/Artemis.UI.Shared/DataModelVisualization/Shared/DataModelListViewModel.cs

@@ -105,20 +105,25 @@ namespace Artemis.UI.Shared
         protected DataModelVisualizationViewModel CreateListChild(IDataModelUIService dataModelUIService, object listItem)
         {
             var listType = listItem.GetType();
-            var path = new DataModelPath(listItem, "");
 
             // If a display VM was found, prefer to use that in any case
             var typeViewModel = dataModelUIService.GetDataModelDisplayViewModel(listType);
             if (typeViewModel != null)
-                return new DataModelListPropertyViewModel(DataModel, this, path) {DisplayViewModel = typeViewModel};
+                return new DataModelListPropertyViewModel(DataModel, listItem, typeViewModel);
             // For primitives, create a property view model, it may be null that is fine
             if (listType.IsPrimitive || listType.IsEnum || listType == typeof(string))
-                return new DataModelListPropertyViewModel(DataModel, this, path) {ListType = listType};
+                return new DataModelListPropertyViewModel(DataModel, listItem);
             // For other value types create a child view model
             if (listType.IsClass || listType.IsStruct())
-                return new DataModelListPropertiesViewModel(DataModel, this, path) {ListType = listType};
+                return new DataModelListPropertiesViewModel(DataModel, listItem);
 
             return null;
         }
+
+        /// <inheritdoc />
+        public override string ToString()
+        {
+            return $"[List] {DisplayPath ?? Path} - {List.Count} item(s)";
+        }
     }
 }

src/Artemis.UI.Shared/DataModelVisualization/Shared/DataModelPropertiesViewModel.cs

@@ -13,7 +13,7 @@ namespace Artemis.UI.Shared
         public override void Update(IDataModelUIService dataModelUIService)
         {
             // Always populate properties
-            PopulateProperties(dataModelUIService);
+            PopulateProperties(dataModelUIService, null);
 
             // Only update children if the parent is expanded
             if (Parent != null && !Parent.IsVisualizationExpanded && !Parent.IsRootViewModel)
@@ -28,9 +28,15 @@ namespace Artemis.UI.Shared
             return Parent.IsRootViewModel ? DataModel : base.GetCurrentValue();
         }
 
-        protected override int GetChildDepth()
+        internal override int GetChildDepth()
         {
             return PropertyDescription != null && !PropertyDescription.ResetsDepth ? Depth + 1 : 1;
         }
+
+        /// <inheritdoc />
+        public override string ToString()
+        {
+            return DisplayPath ?? Path;
+        }
     }
 }

src/Artemis.UI.Shared/DataModelVisualization/Shared/DataModelPropertyViewModel.cs

@@ -50,5 +50,11 @@ namespace Artemis.UI.Shared
         {
             DisplayViewModel?.UpdateValue(DisplayValue);
         }
+
+        /// <inheritdoc />
+        public override string ToString()
+        {
+            return $"[{DisplayValueType.Name}] {DisplayPath ?? Path} - {DisplayValue}";
+        }
     }
 }

src/Artemis.UI.Shared/DataModelVisualization/Shared/DataModelVisualizationViewModel.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections;
+using System.Collections.ObjectModel;
 using System.Linq;
 using System.Reflection;
 using Artemis.Core;
@@ -136,21 +137,6 @@ namespace Artemis.UI.Shared
                 IsMatchingFilteredTypes = filteredTypes.Any(t => t == type || t == typeof(Enum) && type.IsEnum);
         }
 
-        public DataModelVisualizationViewModel GetChildForCondition(DataModelConditionPredicate predicate, DataModelConditionSide side)
-        {
-            if (side == DataModelConditionSide.Left)
-            {
-                if (predicate.LeftDataModel == null || predicate.LeftPropertyPath == null)
-                    return null;
-
-                return GetChildByPath(predicate.LeftDataModel.PluginInfo.Guid, predicate.LeftPropertyPath);
-            }
-
-            if (predicate.RightDataModel == null || predicate.RightPropertyPath == null)
-                return null;
-            return GetChildByPath(predicate.RightDataModel.PluginInfo.Guid, predicate.RightPropertyPath);
-        }
-
         public DataModelVisualizationViewModel GetChildByPath(Guid dataModelGuid, string propertyPath)
         {
             if (DataModel.PluginInfo.Guid != dataModelGuid)
@@ -183,31 +169,44 @@ namespace Artemis.UI.Shared
             return null;
         }
 
-        protected virtual int GetChildDepth()
+        internal virtual int GetChildDepth()
         {
             return 0;
         }
 
-        protected void PopulateProperties(IDataModelUIService dataModelUIService)
+        internal void PopulateProperties(IDataModelUIService dataModelUIService, object overrideValue)
         {
-            if (IsRootViewModel)
+            if (IsRootViewModel && overrideValue == null)
                 return;
 
+            Type modelType;
+            if (overrideValue != null)
+                modelType = overrideValue.GetType();
+            else if (Parent.IsRootViewModel)
+                modelType = DataModel.GetType();
+            else
+                modelType = DataModelPath.GetPropertyType();
+
             // Add missing static children
-            var modelType = Parent.IsRootViewModel ? DataModel.GetType() : DataModelPath.GetPropertyType();
             foreach (var propertyInfo in modelType.GetProperties(BindingFlags.Public | BindingFlags.Instance))
             {
                 var childPath = Path != null ? $"{Path}.{propertyInfo.Name}" : propertyInfo.Name;
                 if (Children.Any(c => c.Path != null && c.Path.Equals(childPath)))
                     continue;
+                if (propertyInfo.GetCustomAttribute<DataModelIgnoreAttribute>() != null)
+                    continue;
 
-                var child = CreateChild(dataModelUIService, childPath, GetChildDepth());
+                var child = CreateChild(dataModelUIService, childPath, GetChildDepth(), overrideValue);
                 if (child != null)
                     Children.Add(child);
             }
 
             // Remove static children that should be hidden
-            var hiddenProperties = DataModel.GetHiddenProperties();
+            ReadOnlyCollection<PropertyInfo> hiddenProperties;
+            if (overrideValue != null && overrideValue is DataModel overrideValueDataModel)
+                hiddenProperties = overrideValueDataModel.GetHiddenProperties();
+            else
+                hiddenProperties = DataModel.GetHiddenProperties();
             foreach (var hiddenProperty in hiddenProperties)
             {
                 var childPath = Path != null ? $"{Path}.{hiddenProperty.Name}" : hiddenProperty.Name;
@@ -217,7 +216,11 @@ namespace Artemis.UI.Shared
             }
 
             // Add missing dynamic children
-            var value = Parent.IsRootViewModel ? DataModel : DataModelPath.GetValue();
+            object value;
+            if (overrideValue != null)
+                value = overrideValue;
+            else
+                value = Parent.IsRootViewModel ? DataModel : DataModelPath.GetValue();
             if (value is DataModel dataModel)
             {
                 foreach (var kvp in dataModel.DynamicDataModels)
@@ -226,7 +229,7 @@ namespace Artemis.UI.Shared
                     if (Children.Any(c => c.Path != null && c.Path.Equals(childPath)))
                         continue;
 
-                    var child = CreateChild(dataModelUIService, childPath, GetChildDepth());
+                    var child = CreateChild(dataModelUIService, childPath, GetChildDepth(), overrideValue);
                     if (child != null)
                         Children.Add(child);
                 }
@@ -238,12 +241,12 @@ namespace Artemis.UI.Shared
                 Children.RemoveRange(toRemoveDynamic);
         }
 
-        protected DataModelVisualizationViewModel CreateChild(IDataModelUIService dataModelUIService, string path, int depth)
+        private DataModelVisualizationViewModel CreateChild(IDataModelUIService dataModelUIService, string path, int depth, object overrideValue)
         {
             if (depth > MaxDepth)
                 return null;
 
-            var dataModelPath = new DataModelPath(DataModel, path);
+            var dataModelPath = new DataModelPath(overrideValue ?? DataModel, path);
             if (!dataModelPath.IsValid)
                 return null;