title: Read Web.config settings from comma-delimited string
body: <p>I am reading specific AppSetting key/value pairs in Web.config, using hard-coded values, with the code below.  This works.</p>
  
  <pre><code>string[] filteredList = webConfigApp.AppSettings.Settings.AllKeys.AsEnumerable().Where(x =&gt; x.Equals("appMode") || x.Equals("loggingMode") || x.Equals("ticketModeCache") || x.Equals("ticketMode")).ToArray();
  </code></pre>
  
  <p>Instead, I would like to read from a comma-separated list that is also in Web.config, for example:</p>
  
  <pre><code>&lt;add key="setConfigValues" value="appMode,loggingMode,ticketModeCache,ticketMode,twilioMode,kioskId,kioskPrinterConfig" /&gt;
  </code></pre>
  
  <p>I know how to to parse and create a List&lt;> doing something along these lines... </p>
  
  <pre><code>List&lt;string&gt; ConfigValues = ConfigurationManager.AppSettings["setConfigValues"].Split(',').ToList();
  </code></pre>
  
  <p>...but I am not sure how to code the Linq part to include values in the List.</p>
  
  <p>How can I do this?  I tried x.Contains but that does not work (understandably).  I am looking to find AppSetting keys that are in the comma-delimited list.  Thanks.</p>