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diff --git a/src/mscorlib/shared/System/Collections/IDictionaryEnumerator.cs b/src/mscorlib/shared/System/Collections/IDictionaryEnumerator.cs
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+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace System.Collections
+{
+    // This interface represents an enumerator that allows sequential access to the
+    // elements of a dictionary. Upon creation, an enumerator is conceptually
+    // positioned before the first element of the enumeration. The first call to the
+    // MoveNext method brings the first element of the enumeration into view,
+    // and each successive call to MoveNext brings the next element into
+    // view until MoveNext returns false, indicating that there are no more
+    // elements to enumerate. Following each call to MoveNext, the
+    // Key and Value methods are used to obtain the key and
+    // value of the element currently in view. The values returned by calls to
+    // Key and Value are undefined before the first call to
+    // MoveNext and following a call to MoveNext that returned false.
+    // Enumerators are typically used in while loops of the form
+    // 
+    // IDictionaryEnumerator e = ...;
+    // while (e.MoveNext()) {
+    //     Object key = e.Key;
+    //     Object value = e.Value;
+    //     ...
+    // }
+    // 
+    // The IDictionaryEnumerator interface extends the IEnumerator
+    // inerface and can thus be used as a regular enumerator. The Current 
+    // method of an IDictionaryEnumerator returns a DictionaryEntry containing
+    // the current key and value pair.  However, the GetEntry method will
+    // return the same DictionaryEntry and avoids boxing the DictionaryEntry (boxing
+    // is somewhat expensive).
+    // 
+    public interface IDictionaryEnumerator : IEnumerator
+    {
+        // Returns the key of the current element of the enumeration. The returned
+        // value is undefined before the first call to GetNext and following
+        // a call to GetNext that returned false. Multiple calls to
+        // GetKey with no intervening calls to GetNext will return
+        // the same object.
+        // 
+        Object Key
+        {
+            get;
+        }
+
+        // Returns the value of the current element of the enumeration. The
+        // returned value is undefined before the first call to GetNext and
+        // following a call to GetNext that returned false. Multiple calls
+        // to GetValue with no intervening calls to GetNext will
+        // return the same object.
+        // 
+        Object Value
+        {
+            get;
+        }
+
+        // GetBlock will copy dictionary values into the given Array.  It will either
+        // fill up the array, or if there aren't enough elements, it will
+        // copy as much as possible into the Array.  The number of elements
+        // copied is returned.
+        // 
+        DictionaryEntry Entry
+        {
+            get;
+        }
+    }
+}