title: Stringbuilder append form from multiple arrays
body: <p>I have a <code>StringBuilder</code> and I'm trying to append parameters from multiple lists like this:</p>
  
  <pre><code>var sb = new StringBuilder();
  var list1 = new List&lt;string&gt;() { "a", "b", "c" }
  var list2 = new List&lt;string&gt;() { "d", "e" }
  sb.AppendFormat(" {0}, {1}, {2}, {3}, {4} ", list1, list2);
  </code></pre>
  
  <p>I get an exception :</p>
  
  <blockquote>
    <p>Index (zero based) must be greater than or equal to zero and less
    than the size of the argument list.</p>
  </blockquote>
  
  <p>What I did to make it work is create a temporary list</p>
  
  <pre><code>var temp = new List&lt;string&gt;();
  temp.AddRange(list1);
  temp.AddRange(list2);
  sb.AppendFormat(" {0}, {1} ,{2}  ,{3}  ,{4} ", new List().Add);
  </code></pre>
  
  <p>Is there a more elegant way to do this ?</p>