[DotNetDevelopment] foreach vs. IEnumerator

[John Smith]

I am a beginner of C# .NET.  Found the following code snippet on
http://msdn.microsoft.com/en-us/library/system.collections.dictionarybase.aspx

What are some examples / use cases where the use of enumerator is
preferrable over foreach?
Thanks.

   // Uses the foreach statement which hides the complexity of the
enumerator.
   // NOTE: The foreach statement is the preferred way of enumerating
the contents of a collection.
   public static void PrintKeysAndValues1( ShortStringDictionary
myCol )  {
      foreach ( DictionaryEntry myDE in myCol )
         Console.WriteLine( "   {0,-5} : {1}", myDE.Key, myDE.Value );
      Console.WriteLine();
   }

   // Uses the enumerator.
   // NOTE: The foreach statement is the preferred way of enumerating
the contents of a collection.
   public static void PrintKeysAndValues2( ShortStringDictionary
myCol )  {
      DictionaryEntry myDE;
      System.Collections.IEnumerator myEnumerator =
myCol.GetEnumerator();
      while ( myEnumerator.MoveNext() )
         if ( myEnumerator.Current != null )  {
            myDE = (DictionaryEntry) myEnumerator.Current;
            Console.WriteLine( "   {0,-5} : {1}", myDE.Key,
myDE.Value );
         }
      Console.WriteLine();
   }