Data model paths - Added events for validating/invalidating

List condition - Reinitialize when path validates/invalidates
Conditions - Don't save with invalid paths
Core - Fixed render exception on data model expansion deactivate

src/Artemis.Core/Models/Profile/Conditions/DataModelConditionList.cs

@@ -13,6 +13,7 @@ namespace Artemis.Core
     public class DataModelConditionList : DataModelConditionPart
     {
         private bool _disposed;
+        private bool _reinitializing;
 
         /// <summary>
         ///     Creates a new instance of the <see cref="DataModelConditionList" /> class
@@ -83,6 +84,7 @@ namespace Artemis.Core
 
             ListPath?.Dispose();
             ListPath = path != null ? new DataModelPath(path) : null;
+            SubscribeToListPath();
 
             // Remove the old root group that was tied to the old data model
             while (Children.Any())
@@ -143,6 +145,10 @@ namespace Artemis.Core
 
         internal override void Save()
         {
+            // Don't save an invalid state
+            if (ListPath != null && !ListPath.IsValid)
+                return;
+
             // Target list
             ListPath?.Save();
             Entity.ListPath = ListPath?.Entity;
@@ -164,6 +170,9 @@ namespace Artemis.Core
 
         internal void Initialize()
         {
+            while (Children.Any())
+                RemoveChild(Children[0]);
+
             if (Entity.ListPath == null)
                 return;
 
@@ -175,6 +184,7 @@ namespace Artemis.Core
                 return;
 
             ListPath = listPath;
+            SubscribeToListPath();
             if (ListPath.IsValid)
             {
                 ListType = listType.GetGenericArguments()[0];
@@ -187,7 +197,7 @@ namespace Artemis.Core
             }
 
             // There should only be one child and it should be a group
-            if (Entity.Children.SingleOrDefault() is DataModelConditionGroupEntity rootGroup)
+            if (Entity.Children.FirstOrDefault() is DataModelConditionGroupEntity rootGroup)
             {
                 AddChild(new DataModelConditionGroup(this, rootGroup));
             }
@@ -197,6 +207,39 @@ namespace Artemis.Core
                 AddChild(new DataModelConditionGroup(this));
             }
         }
+
+        private void SubscribeToListPath()
+        {
+            if (ListPath == null) return;
+            ListPath.PathValidated += ListPathOnPathValidated;
+            ListPath.PathInvalidated += ListPathOnPathInvalidated;
+        }
+
+        #region Event handlers
+
+        private void ListPathOnPathValidated(object? sender, EventArgs e)
+        {
+            if (_reinitializing)
+                return;
+
+            _reinitializing = true;
+            ListPath?.Dispose();
+            Initialize();
+            _reinitializing = false;
+        }
+
+        private void ListPathOnPathInvalidated(object? sender, EventArgs e)
+        {
+            if (_reinitializing)
+                return;
+
+            _reinitializing = true;
+            ListPath?.Dispose();
+            Initialize();
+            _reinitializing = false;
+        }
+
+        #endregion
     }
 
     /// <summary>

src/Artemis.Core/Models/Profile/Conditions/DataModelConditionPredicate.cs

@@ -205,6 +205,10 @@ namespace Artemis.Core
 
         internal override void Save()
         {
+            // Don't save an invalid state
+            if (LeftPath != null && !LeftPath.IsValid || RightPath != null && !RightPath.IsValid)
+                return;
+
             Entity.PredicateType = (int) PredicateType;
 
             LeftPath?.Save();

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

@@ -14,9 +14,9 @@ namespace Artemis.Core
     /// </summary>
     public class DataModelPath : IStorageModel, IDisposable
     {
-        private bool _disposed;
         private readonly LinkedList<DataModelPathSegment> _segments;
         private Expression<Func<object, object>>? _accessorLambda;
+        private bool _disposed;
 
         /// <summary>
         ///     Creates a new instance of the <see cref="DataModelPath" /> class pointing directly to the target
@@ -59,7 +59,7 @@ namespace Artemis.Core
         /// <param name="dataModelPath">The path to base the new instance on</param>
         public DataModelPath(DataModelPath dataModelPath)
         {
-            if (dataModelPath == null) 
+            if (dataModelPath == null)
                 throw new ArgumentNullException(nameof(dataModelPath));
 
             Target = dataModelPath.Target;
@@ -188,6 +188,8 @@ namespace Artemis.Core
 
             _accessorLambda = null;
             Accessor = null;
+
+            OnPathInvalidated();
         }
 
         internal void Initialize()
@@ -239,6 +241,9 @@ namespace Artemis.Core
                 ),
                 parameter
             );
+
+            if (IsValid)
+                OnPathValidated();
         }
 
         private void SubscribeToDataModelStore()
@@ -307,5 +312,29 @@ namespace Artemis.Core
         }
 
         #endregion
+
+        #region Events
+
+        /// <summary>
+        ///     Occurs whenever the path becomes invalid
+        /// </summary>
+        public event EventHandler PathInvalidated;
+
+        /// <summary>
+        ///     Occurs whenever the path becomes valid
+        /// </summary>
+        public event EventHandler PathValidated;
+
+        protected virtual void OnPathValidated()
+        {
+            PathValidated?.Invoke(this, EventArgs.Empty);
+        }
+
+        protected virtual void OnPathInvalidated()
+        {
+            PathInvalidated?.Invoke(this, EventArgs.Empty);
+        }
+
+        #endregion
     }
 }

src/Artemis.Core/Services/CoreService.cs

@@ -166,8 +166,8 @@ namespace Artemis.Core.Services
                 _frameStopWatch.Restart();
                 lock (_dataModelExpansions)
                 {
-                    // Update all active modules
-                    foreach (BaseDataModelExpansion dataModelExpansion in _dataModelExpansions)
+                    // Update all active modules, check Enabled status because it may go false before before the _dataModelExpansions list is updated
+                    foreach (BaseDataModelExpansion dataModelExpansion in _dataModelExpansions.Where(e => e.Enabled)) 
                         dataModelExpansion.Update(args.DeltaTime);
                 }
 

src/Artemis.UI/Screens/ProfileEditor/Conditions/DataModelConditionGroupView.xaml

@@ -146,7 +146,7 @@
             <materialDesign:PackIcon Kind="Add" Width="18" Height="18" />
         </Button>
 
-        <ItemsControl Grid.Row="1" Grid.Column="1" Grid.ColumnSpan="2" ItemsSource="{Binding Items}">
+        <ItemsControl Grid.Row="1" Grid.Column="1" Grid.ColumnSpan="2" ItemsSource="{Binding Items, IsAsync=True}">
             <ItemsControl.ItemTemplate>
                 <DataTemplate>
                     <ContentControl s:View.Model="{Binding}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch" IsTabStop="False" />