Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.ServiceModel.Internals/System/Runtime/ReadOnlyKeyedCollection.cs

@@ -0,0 +1,29 @@
+//-----------------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+//-----------------------------------------------------------------------------
+
+namespace System.Runtime
+{
+    using System.Collections.ObjectModel;
+
+    class ReadOnlyKeyedCollection<TKey, TValue> : ReadOnlyCollection<TValue>
+    {
+        KeyedCollection<TKey, TValue> innerCollection;
+
+        public ReadOnlyKeyedCollection(KeyedCollection<TKey, TValue> innerCollection)
+            : base(innerCollection)
+        {
+            Fx.Assert(innerCollection != null, "innerCollection should not be null");
+            this.innerCollection = innerCollection;
+        }
+
+        public TValue this[TKey key]
+        {
+            get
+            {
+                return this.innerCollection[key];
+            }
+        }
+    }
+
+}