Moved StyleResources to its own file.

And don't inherit from Dictionary, instead implement `IDictionary<,>`.

src/Avalonia.Styling/Avalonia.Styling.csproj

@@ -55,6 +55,7 @@
     <Compile Include="Controls\INameScope.cs" />
     <Compile Include="Styling\ITemplate.cs" />
     <Compile Include="Controls\NameScope.cs" />
+    <Compile Include="Styling\StyleResources.cs" />
     <Compile Include="Styling\TemplateSelector.cs" />
     <Compile Include="Styling\DescendentSelector.cs" />
     <Compile Include="Styling\ChildSelector.cs" />

src/Avalonia.Styling/Styling/Style.cs

@@ -180,8 +180,4 @@ namespace Avalonia.Styling
             _applied.Remove(control);
         }
     }
-
-    public class StyleResources : Dictionary<string, object>
-    {
-    }
 }

src/Avalonia.Styling/Styling/StyleResources.cs

@@ -0,0 +1,90 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+
+namespace Avalonia.Styling
+{
+    /// <summary>
+    /// Holds resources for a <see cref="Style"/>.
+    /// </summary>
+    public class StyleResources : IDictionary<string, object>, IDictionary
+    {
+        private Dictionary<string, object> _inner = new Dictionary<string, object>();
+
+        public object this[string key]
+        {
+            get { return _inner[key]; }
+            set { _inner[key] = value; }
+        }
+
+        public int Count => _inner.Count;
+
+        ICollection<string> IDictionary<string, object>.Keys => _inner.Keys;
+
+        ICollection<object> IDictionary<string, object>.Values => _inner.Values;
+
+        bool ICollection<KeyValuePair<string, object>>.IsReadOnly => false;
+
+        object IDictionary.this[object key]
+        {
+            get { return ((IDictionary)_inner)[key]; }
+            set { ((IDictionary)_inner)[key] = value; }
+        }
+
+        ICollection IDictionary.Keys => _inner.Keys;
+
+        ICollection IDictionary.Values => _inner.Values;
+
+        bool ICollection.IsSynchronized => false;
+
+        object ICollection.SyncRoot => ((IDictionary)_inner).SyncRoot;
+
+        bool IDictionary.IsFixedSize => false;
+
+        bool IDictionary.IsReadOnly => false;
+
+        public void Add(string key, object value) => _inner.Add(key, value);
+
+        public void Clear() => _inner.Clear();
+
+        public bool ContainsKey(string key) => _inner.ContainsKey(key);
+
+        public bool Remove(string key) => _inner.Remove(key);
+
+        public IEnumerator<KeyValuePair<string, object>> GetEnumerator() => _inner.GetEnumerator();
+
+        public bool TryGetValue(string key, out object value) => _inner.TryGetValue(key, out value);
+
+        bool ICollection<KeyValuePair<string, object>>.Contains(KeyValuePair<string, object> item)
+        {
+            return ((IDictionary<string, object>)_inner).Contains(item);
+        }
+
+        void ICollection<KeyValuePair<string, object>>.Add(KeyValuePair<string, object> item)
+        {
+            ((IDictionary<string, object>)_inner).Add(item);
+        }
+
+        void ICollection<KeyValuePair<string, object>>.CopyTo(KeyValuePair<string, object>[] array, int arrayIndex)
+        {
+            ((IDictionary<string, object>)_inner).CopyTo(array, arrayIndex);
+        }
+
+        bool ICollection<KeyValuePair<string, object>>.Remove(KeyValuePair<string, object> item)
+        {
+            return ((IDictionary<string, object>)_inner).Remove(item);
+        }
+
+        void ICollection.CopyTo(Array array, int index) => ((IDictionary)_inner).CopyTo(array, index);
+
+        IEnumerator IEnumerable.GetEnumerator() => _inner.GetEnumerator();
+
+        IDictionaryEnumerator IDictionary.GetEnumerator() => ((IDictionary)_inner).GetEnumerator();
+
+        void IDictionary.Add(object key, object value) => ((IDictionary)_inner).Add(key, value);
+
+        bool IDictionary.Contains(object key) => ((IDictionary)_inner).Contains(key);
+
+        void IDictionary.Remove(object key) => ((IDictionary)_inner).Remove(key);
+    }
+}