title: Class 'clsGetHeaderValue' cannot be indexed because it has no default property
body: <p>I am getting a strange error when I try to build my solution. The error occurs when I am calling the <strong>oGetHeaderValue</strong> function and passing the parameters.  </p>
  
  <pre><code>Dim oGetHeaderValue As New clsGetHeaderValue
  
  Dim returnString As String
  returnString = oGetHeaderValue(strInvoiceNumber, strOrderNumber)
  </code></pre>
  
  <p>The error message is: Class 'clsGetHeaderValue' cannot be indexed because it has no default property.</p>