title: 'Nullable object must have a value.' for List in LINQ c#
body: <p>In database I have next model <code>tblWorkItem</code> with next field:</p>
  
  <pre><code>public List&lt;xWorkItemItemFailReason&gt; WorkItemItemFailReasons { get; set; }
  </code></pre>
  
  <p>When I am trying to get <code>tblWorkItem</code> data from database</p>
  
  <pre><code>_db.tblWorkItem.Where(x=&gt;x.WorkItemItemFailReasons != null)
  </code></pre>
  
  <p>I have next error </p>
  
  <blockquote>
    <p>System.InvalidOperationException: 'Nullable object must have a value.'</p>
  </blockquote>
  
  <p>How I can check if this field is not null? </p>