title: String.IsNullOrEmpty and Datarow.IsXnull
body: <p>How can I improve this code?  What has made this long winded is the fact that I can't use string.IsNullOrEmpty on a data row and instead I have to use a dr.IsHOUSENUMBERNull method AND the string.IsNullOrEmpty to check if it is empty.  Why is this?  The column in the database is sometimes empty and sometimes NULL.</p>
  
  <p>I'm sure this can be written better:</p>
  
  <pre><code>     If Not dr.IsHOUSENUMBERNull Then
             If Not String.IsNullOrEmpty(dr.HOUSENUMBER) Then
                  sbAddress.AppendLine(dr.HOUSENUMBER + " " + dr.ADDRESS1)
             Else
                  sbAddress.AppendLine(dr.ADDRESS1)
             End If   
       Else
             sbAddress.AppendLine(dr.ADDRESS1)      
       End If
  </code></pre>