title: Null value in linq where clause
body: <p>I'm having an issue where I want to return results where something matches and I get an error if one of the properties I'm trying to match is null.</p>
  
  <pre><code>  if (!string.IsNullOrEmpty(searchString))
    {
        Infos = Infos.Where(
            x =&gt;
            x.FirstName.ToLower().Contains(searchString) ||
            x.LastName.ToLower().Contains(searchString) ||
            x.ContractNum.ToLower().Contains(searchString) ||
            x.VIN.ToLower().Contains(searchString) ||
            x.Claim.InitiatedBy.ToLower().Contains(searchString)
            ).ToList();
    }
  </code></pre>
  
  <p>If <code>ContractNum</code> or <code>VIN</code>, for example, are null then it throws an error. I'm not sure how to check if one of these are null inside of a linq query.</p>