title: A dictionary with multiple entries with the same key
body: <p>I need a Dictionary like object that can store multiple entries with the same key.  Is this avaliable as a standard collection, or do I need to roll my own?</p>
  
  <p>To clarify, I want to be able to do something like this:</p>
  
  <pre><code>var dict = new Dictionary&lt;int, String&gt;();
  dict.Add(1, "first");
  dict.Add(1, "second");
  
  foreach(string x in dict[1])
  {
      Console.WriteLine(x);
  }
  </code></pre>
  
  <p>Output:</p>
  
  <pre><code>first
  second
  </code></pre>