title: Iterating through a list of lists?
body: <p>I have Items from a certain source (populated from somewhere else):</p>
  
  <pre><code>public class ItemsFromSource{
      public ItemsFromSource(string name){
          this.SourceName = name;
          Items = new List&lt;IItem&gt;();
      }
  
      public string SourceName;
      public List&lt;IItem&gt; Items;
  }
  </code></pre>
  
  <p>Now in MyClass I have Items from several sources (populated from somewhere else):</p>
  
  <pre><code>public class MyClass{
      public MyClass(){
      }
  
      public List&lt;ItemsFromSource&gt; BunchOfItems;
  }
  </code></pre>
  
  <p>Is there a simple way to iterate through all Items in all ItemsFromSources in BunchOfItems in one go?
  i.e., something like:</p>
  
  <pre><code>foreach(IItem i in BunchOfItems.AllItems()){
      // do something with i
  }
  </code></pre>
  
  <p>instead of doing</p>
  
  <pre><code>foreach(ItemsFromSource ifs in BunchOffItems){
      foreach(IItem i in ifs){
          //do something with i
      }
  }
  </code></pre>