<p>Are there any dictionary classes in the .NET base class library which allow duplicate keys to be used?  The only solution I've found is to create, for example, a class like:</p>

<pre><code>Dictionary&lt;string, List&lt;object&gt;&gt;
</code></pre>

<p>But this is quite irritating to actually use.  In Java, I believe a MultiMap accomplishes this, but cannot find an analog in .NET.</p>

I think something like
```
List<KeyValuePair<object, object>>
```
would do the Job.