title: Calculate GroupSummary Value programmatically in DevExpress
body: <p>In my code; I calculate 3 <code>GroupSummary</code> value with <code>ASPxGridview</code>;</p>
  
  <pre><code>&lt;dx:ASPxSummaryItem FieldName="RISK_EUR" SummaryType="SUM" ShowInGroupFooterColumn="RISK_EUR" DisplayFormat="n0" /&gt;
  &lt;dx:ASPxSummaryItem FieldName="IPOTEK" SummaryType="AVERAGE" ShowInGroupFooterColumn="IPOTEK" DisplayFormat="n0" /&gt;
  &lt;dx:ASPxSummaryItem FieldName="MV_BERND" SummaryType="SUM" ShowInGroupFooterColumn="MV_BERND" DisplayFormat="n0" /&gt;
  </code></pre>
  
  <p><strong>When i grouping</strong>, I want calculate another column's GroupSummary value like;</p>
  
  <pre><code> GroupSummary[RISK_EUR] - GroupSummary[IPOTEK] - GroupSummary[MV_BERND]
  </code></pre>
  
  <p>How?</p>
  
  <p><strong>NOTE</strong>: I can't calculate this value calculating for every row and then total them, because this 3 GroupSummary's SummaryType isn't same. (One is AVERAGE)</p>