title: Sequence contains no elements exception in linq without even using Single
body: <p>I am not using <code>Single</code> in LINQ below, but I am still getting a 'Sequence contains no elements' exception:</p>
  
  <pre><code>allNames = StockCollection.Where((s) =&gt; s.Name.IndexOf("A") == 0)
                            .Select((s) =&gt; s.Name)
                            .Aggregate((namesInfo, name) =&gt; namesInfo += ", " + name);
  </code></pre>
  
  <p>This exception comes when there is no stock starting with name <code>'A'</code>.</p>
  
  <p>It seems that one extension method is expecting atleast one element satisfying the condition but that's not expected.</p>
  
  <p>Can you please suggest the best solution to resolve this?</p>
  
  <p>Thanks in advance.</p>