title: 3-Way sorting in ultragrid
body: <p>how can i have a ultragrid with 3-way sorting on every columns? I mean :</p>
  
  <p>a. Ascendiing -Indicated by default ascending SortIndicator.</p>
  
  <p>b. Descending- Indicated by default descending SortIndicator.</p>
  
  <p>c. No Sort- UnSort the column. </p>
  
  <p>Note: I have tried BeforeSortChanged Event but i had 2 problems:</p>
  
  <ol>
  <li><p>I could not get the previous column sort indicator to find out when
  should i disable sorting.</p></li>
  <li><p>I have got an Exception where it is saying that we can't change
  SortIndicator in BeforeSortChange Event</p></li>
  </ol>