Revert "Improve performance of DynamicResource usages (dotnet#5610)"

This reverts commit 38a157c.

Author: harshit7962

src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/ResourceDictionary.cs

@@ -1735,31 +1735,23 @@ private object FetchResource(
                     DeferredResourceReference deferredResourceReference;
                     if (!IsThemeDictionary)
                     {
-                        // Cache the deferredResourceReference so that it can be validated
-                        // in case of a dictionary change prior to its inflation
-                        if (_deferredResourceReferences == null)
-                        {
-                            _deferredResourceReferences = new DeferredResourceReferenceList();
-                        }
-
-                        if (_deferredResourceReferences.Get(resourceKey) is { } existingDeferredResourceReference
-                            && existingDeferredResourceReference.Dictionary == this)
+                        if (_ownerApps != null)
                         {
-                            deferredResourceReference = existingDeferredResourceReference;
+                            deferredResourceReference = new DeferredAppResourceReference(this, resourceKey);
                         }
                         else
                         {
-                            if (_ownerApps != null)
-                            {
-                                deferredResourceReference = new DeferredAppResourceReference(this, resourceKey);
-                            }
-                            else
-                            {
-                                deferredResourceReference = new DeferredResourceReference(this, resourceKey);
-                            }
+                            deferredResourceReference = new DeferredResourceReference(this, resourceKey);
+                        }
 
-                            _deferredResourceReferences.AddOrSet(deferredResourceReference);
+                        // Cache the deferredResourceReference so that it can be validated
+                        // in case of a dictionary change prior to its inflation
+                        if (_deferredResourceReferences == null)
+                        {
+                            _deferredResourceReferences = new WeakReferenceList();
                         }
+
+                        _deferredResourceReferences.Add( deferredResourceReference, true /*SkipFind*/);
                     }
                     else
                     {
@@ -1783,18 +1775,22 @@ private void ValidateDeferredResourceReferences(object resourceKey)
         {
             if (_deferredResourceReferences != null)
             {
-                DeferredResourceReference deferredResourceReference = _deferredResourceReferences.Get(resourceKey);
-
-                if (deferredResourceReference is not null)
+                foreach (Object o in _deferredResourceReferences)
                 {
-                    // This will inflate the deferred reference, causing it
-                    // to be removed from the list.  The list may also be
-                    // purged of dead references.
-                    deferredResourceReference.GetValue(BaseValueSourceInternal.Unknown);
+
+                    DeferredResourceReference deferredResourceReference = o as DeferredResourceReference;
+                    if (deferredResourceReference != null && (resourceKey == null || Object.Equals(resourceKey, deferredResourceReference.Key)))
+                    {
+                        // This will inflate the deferred reference, causing it
+                        // to be removed from the list.  The list may also be
+                        // purged of dead references.
+                        deferredResourceReference.GetValue(BaseValueSourceInternal.Unknown);
+                    }
                 }
             }
         }
 
+
         /// <summary>
         /// Called when the MergedDictionaries collection changes
         /// </summary>
@@ -2057,7 +2053,7 @@ internal WeakReferenceList ApplicationOwners
 
         #region Properties
 
-        internal DeferredResourceReferenceList DeferredResourceReferences
+        internal WeakReferenceList DeferredResourceReferences
         {
             get { return _deferredResourceReferences; }
         }
@@ -2482,7 +2478,10 @@ private void  MoveDeferredResourceReferencesFrom(ResourceDictionary loadedRD)
             // redirect each entry toward its new owner
             if (_deferredResourceReferences != null)
             {
-                _deferredResourceReferences.ChangeDictionary(this);
+                foreach (DeferredResourceReference drr in _deferredResourceReferences)
+                {
+                    drr.Dictionary = this;
+                }
             }
         }
 
@@ -2549,7 +2548,7 @@ private enum FallbackState
         private WeakReferenceList                         _ownerFEs = null;
         private WeakReferenceList                         _ownerFCEs = null;
         private WeakReferenceList                         _ownerApps = null;
-        private DeferredResourceReferenceList             _deferredResourceReferences = null;
+        private WeakReferenceList                         _deferredResourceReferences = null;
         private ObservableCollection<ResourceDictionary>  _mergedDictionaries = null;
         private Uri                                       _source = null;
         private Uri                                       _baseUri = null;

src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/SystemResources.cs

@@ -1745,9 +1745,8 @@ internal override object GetValue(BaseValueSourceInternal valueSource)
                 {
                     // Note that we are replacing the _keyorValue field
                     // with the value and deleting the _dictionary field.
-                    RemoveFromDictionary();
-                    // Update after removal from dictionary as we need the key for proper removal
                     _keyOrValue = value;
+                    RemoveFromDictionary();
                 }
 
                 // Freeze if this value originated from a style or template
@@ -2039,103 +2038,9 @@ internal override bool IsUnset
 
         #endregion Properties
     }
+}
 
-    internal class DeferredResourceReferenceList
-    {
-        private readonly object _syncRoot = new();
-        private readonly Dictionary<object, WeakReference<DeferredResourceReference>> _entries = new();
-        private int _potentiallyDeadEntryCount = 0;
-
-        public void AddOrSet(DeferredResourceReference deferredResourceReference)
-        {
-            lock (_syncRoot)
-            {
-                _entries[deferredResourceReference.Key] = new WeakReference<DeferredResourceReference>(deferredResourceReference);
-            }
-        }
-
-        public void Remove(DeferredResourceReference deferredResourceReference)
-        {
-            lock (_syncRoot)
-            {
-                _entries.Remove(deferredResourceReference.Key);
-            }
-        }
-
-        internal DeferredResourceReference Get(object resourceKey)
-        {
-            lock (_syncRoot)
-            {
-                _entries.TryGetValue(resourceKey, out var weakReference);
-
-                if (weakReference is null)
-                {
-                    return null;
-                }
-
-                if (weakReference.TryGetTarget(out var deferredResourceReference))
-                {
-                    return deferredResourceReference;
-                }
-                else
-                {
-                    ++_potentiallyDeadEntryCount;
-                }
-            }
-
-            PurgeIfRequired();
-
-            return null;
-        }
-
-        internal void ChangeDictionary(ResourceDictionary resourceDictionary)
-        {
-            lock (_syncRoot)
-            {
-                foreach (WeakReference<DeferredResourceReference> weakReference in _entries.Values)
-                {
-                    if (weakReference.TryGetTarget(out var deferredResourceReference))
-                    {
-                        deferredResourceReference.Dictionary = resourceDictionary;
-                    }
-                    else
-                    {
-                        ++_potentiallyDeadEntryCount;
-                    }
-                }
-            }
-
-            PurgeIfRequired();
-        }
 
-        private void PurgeIfRequired()
-        {
-            if (_potentiallyDeadEntryCount > 25)
-            {
-                Purge();
-            }
-        }
 
-        private void Purge()
-        {
-            lock (_syncRoot)
-            {
-                List<object> deadKeys = new(Math.Min(_potentiallyDeadEntryCount, _entries.Count));
-                _potentiallyDeadEntryCount = 0;
 
-                foreach (KeyValuePair<object, WeakReference<DeferredResourceReference>> entry in _entries)
-                {
-                    if (entry.Value.TryGetTarget(out _) == false)
-                    {
-                        deadKeys.Add(entry.Key);
-                    }
-                }
 
-                foreach (object deadKey in deadKeys)
-                {
-                    _entries.Remove(deadKey);
-                }
-            }
-        }
-    }
-}