title: What to pass as string argument to constructor?
body: <p>I have the following situation:</p>
  
  <pre><code>protected MobileWalletRequestBase(XmlDocument xmlDoc, string request)
  {
      _xmlDoc = xmlDoc;
  }
  
  protected MobileWalletRequestBase()
      : this(new XmlDocument(), ?)
  {
      _xmlDoc.LoadXml("&lt;?xml version=\"1.0\" encoding=\"utf-8\"?&gt;&lt;request/&gt;");
  }
  </code></pre>
  
  <p>What should I write in second constructor in order to pass string value?</p>