Check if value is not on the list : <p>I don't want values from the <code>List&lt;string&gt;</code> to be used. </p>

<p>For <code>List&lt;string&gt;</code> I have a function:</p>

<pre><code>private List&lt;string&gt; GetManualColumns()
{
  List&lt;string&gt; listColumns = new List&lt;string&gt;();
  listColumns.Add("USER_KEY");
  listColumns.Add("USER_NAME");

  return listColumns;
}
</code></pre>

<p>I need to iterate to specific values (column names), but they must not be in the list from function <code>GetManualColumns()</code>.</p>

<p>How to do this?</p>

<p>I need something like:</p>

<pre><code>if(col not in GetManualColumns())
{
}
</code></pre>
