title: MvvmLight SimpleIoc and multiple concrete implementations
body: <p>With <code>SimpleIoc</code> I'd like to register multiple implementations of <code>IProvider</code>, something like:</p>
  
  <pre><code>SimpleIoc.Default.Register&lt;IProvider, Provider1&gt;();
  SimpleIoc.Default.Register&lt;IProvider, Provider2&gt;();
  </code></pre>
  
  <p>So I can do:</p>
  
  <pre><code>var providers = SimpleIoc.GetAllInstances&lt;IProvider&gt;();
  </code></pre>
  
  <p>Is there a way to do something like this?  If I try it as is I get that there is already a class registered for <code>IProvider</code>.</p>