title: Pass null as parameter in Regex.Replace
body: <p>I want to replace value from sql database in mail merging. But I seem to be getting an error message in visual studio.</p>
  
  <blockquote>
    <p>Value cannot be null.
    Parameter name: replacement</p>
  </blockquote>
  
  <p>when I try this </p>
  
  <pre><code>Regex.Replace(mergeFieldsXML.InnerXml,"«[^»]*" + wordtoReplace + "[^»]*»", SecurityElement.Escape(mailMergeData[wordtoReplace ]),RegexOptions.IgnoreCase);
  </code></pre>
  
  <p>I am wondering if it is possible to ignore the null value and continue with the replacement?</p>