The One With

There are 5 build-in aggregate functions that our Silverlight DataGrid supports (Max, Min, Avg, Sum and Count), and an ability to define custom ones.

Using build-in Summary Items

<DevExpress:AgDataGrid>

   <DevExpress:AgDataGrid.Totals>

       <DevExpress:AgDataGridSummaryItem FieldName="Points" SummaryType="Average"/>

       <DevExpress:AgDataGridSummaryItem FieldName="Points" SummaryType="Max"/>

       <DevExpress:AgDataGridSummaryItem FieldName="Points" SummaryType="Min"/>

       <DevExpress:AgDataGridSummaryItem FieldName="Points" SummaryType="Count"/>

       <DevExpress:AgDataGridSummaryItem FieldName="Points" SummaryType="Sum"/>  

   </DevExpress:AgDataGrid.Totals>

</DevExpress>

Calculating Custom Summary

To calculate custom summary, we need to add an AgDataGridSummaryItem with SummaryType of "Custom" and use the AgDataGrid.CustomSummary event.

<DevExpress:AgDataGrid CustomSummary="myGrid_CustomSummary">

   <DevExpress:AgDataGrid.Totals>

         <DevExpress:AgDataGridSummaryItem FieldName="Points" SummaryType="Custom"

                                          Title="Sum Of Even Rows"/>

   </DevExpress:AgDataGrid.Totals>

</DevExpress>

private void myGrid_CustomSummary(object sender, DevExpress.Windows.Data.CustomSummaryEventArgs e) {              

                  if (e.SummaryProcess == CustomSummaryProcess.Start) {

                        int rowHandle = 0;                       

                        int sumOfEvenRows = 0;

                        int i = 1;

                        while (myGrid.IsValidRowHandle(rowHandle)) {

                              Item item = (Item)myGrid.GetDataRow(rowHandle);

                              if ((i % 2) == 0){

                            sumOfEvenRows += item.Points;

                              }

                              rowHandle++;

                              i++;

                        }

                        e.TotalValue = sumOfEvenRows;

                        e.TotalValueReady = true;

               }

}

public class MyRowItem {

      public int Points { get; set; }

}

All we are doing here is going through every row in our data source and summing up the Points for even rows.

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Cheers,

Azret