title: How to Assign the String Array value to Collection or how to compare Array and LIst value
body: <p>I have input of 1,2,3,4 that I will pass to a web service that will return valid ids only.</p>
  
  <p>For example, the list [1,4] is valid, meaning it returns 1 and 4. i need 1 and 4 as valid list and 2 and 3 as invalid list.</p>
  
  <p>I got the valid list from the web service <code>ValidList</code>. The question is, how to get the invalid list.</p>
  
  <pre><code>public ActionResult MethodName(Class LookUp)
  {
  
    int totalRecords;
  
    Collection&lt;Class&gt; ValidList = new Collection&lt;Class&gt;();
    Collection&lt;Class&gt; invalidList = new Collection&lt;Class&gt;();
  
    string[] arrId = LookUp.SearchKey.Split(',');
  
    if (LookUp.SearchKey != "")
    {
      ValidList = Helpers.ProcessException&lt;Collection&lt;Class&gt;&gt;(() =&gt; WebserviceMethodName(LookUp));
    }
  
    totalRecords = ValidList.Count;
  
    // I  Tried This but it wont works
     //invalidList = lookUpList.Select(i =&gt; new { ID = i.ID }).Any(i =&gt; arrId);
  
    // I want Valid and Invalid List 
  
    return Json(lookUpList);                        
  }
  </code></pre>