title: Structuremap, constructor that takes a list of plugins
body: <p>I got an interface like this</p>
  
  <pre><code>public interface IWriter
  {
    ...
  }
  </code></pre>
  
  <p>and a class </p>
  
  <pre><code>public class WriterMerger
  {
    public WriterMerger(IEnumerable&lt;IWriter&gt; writers)
    ...
  }
  </code></pre>
  
  <p>I want structuremap to fill out the constructor argument on WriterMerger with all registered IWriter's.
  I registered the different writers with</p>
  
  <pre><code>StructureMap.ObjectFactory.Initialize(x =&gt;
  {
    x.ForRequestedType&lt;IWriter&gt;().AddConcreteType&lt;MemoryWriter&gt;();
    x.ForRequestedType&lt;IWriter&gt;().AddConcreteType&lt;FlatFileWriter&gt;();
    x.ForRequestedType&lt;IWriter&gt;().AddConcreteType&lt;DbWriter&gt;();
  }
  </code></pre>
  
  <p>however calling</p>
  
  <pre><code>ObjectFactory.CreateInstance&lt;WriterMerger&gt;();
  </code></pre>
  
  <p>Returns an exception <em>"No Default Instance defined for PluginFamily System.Collections.Generic.IEnumerable`1[[IWriter..]]"</em> (class name edited)</p>
  
  <p>Any trick for doing this automatically? or will i have to make a custom factory method?</p>