Custom Summary

Jun 16, 2022
3 minutes to read

Total summaries and group summaries include five predefined aggregate functions that allow you to calculate:

The number of data rows
The maximum and minimum values
The sum and the average value

The ASPxGridBase.CustomSummaryCalculate event allows you to implement a custom summary. For example, custom summaries can calculate summaries against records that meet specific criteria and use multiple data fields in calculations.

Implement Custom Summary

Follow the steps below to implement a custom summary:

Create a summary item and set its ASPxSummaryItemBase.SummaryType property to SummaryItemType.Custom.
Handle the ASPxGridBase.CustomSummaryCalculate event to calculate the summary.

The ASPxGridBase.CustomSummaryCalculate event fires for grid data rows in the following cases:

When you calculate a total summary value, the grid raises this event for each data row.
When you calculate a group summary value, the grid raises this event for each data row in a group.

Note

Note that the grid raises the ASPxGridBase.CustomSummaryCalculate event before and after a row is processed.

The summary calculation consists of three stages:

Initialization
Calculation
Finalization

Example

ASPX
C#
JS

aspx

<dx:ASPxGridView ID="ASPxGridView1" runat="server" OnCustomCallback="ASPxGridView1_CustomCallback" AutoGenerateColumns="False" DataSourceID="SqlDataSource1" ClientInstanceName="grid" Theme="Office365" KeyFieldName="ProductID" OnCustomSummaryCalculate="ASPxGridView1_CustomSummaryCalculate">
    <Columns>
        <dx:GridViewCommandColumn SelectAllCheckboxMode="Page" ShowSelectCheckbox="True" VisibleIndex="0">
        </dx:GridViewCommandColumn>
        <dx:GridViewDataTextColumn FieldName="ProductID" VisibleIndex="1" ReadOnly="True">
            <EditFormSettings Visible="False" />
        </dx:GridViewDataTextColumn>
        <dx:GridViewDataTextColumn FieldName="ProductName" VisibleIndex="2">
        </dx:GridViewDataTextColumn>
        <dx:GridViewDataTextColumn FieldName="UnitPrice" VisibleIndex="3">
        </dx:GridViewDataTextColumn>
    </Columns>
    <Settings ShowFooter="true" />
    <TotalSummary>
        <dx:ASPxSummaryItem SummaryType="Custom" FieldName="UnitPrice" ShowInColumn="UnitPrice" DisplayFormat="Total price for selected products: {0:c}" ValueDisplayFormat="{0}:c" />
    </TotalSummary>
</dx:ASPxGridView>

 

<dx:ASPxButton ID="ASPxButton4" runat="server" Text="Refresh" AutoPostBack="false" Theme="Office365">
    <ClientSideEvents Click="OnClick" />
</dx:ASPxButton>

csharp

protected void ASPxGridView1_CustomSummaryCalculate(object sender, DevExpress.Data.CustomSummaryEventArgs e)
{
    // Initialization. 
    if (e.SummaryProcess == DevExpress.Data.CustomSummaryProcess.Start)
        totalSum = 0;
    else
    // Calculation. 
    if (e.SummaryProcess == DevExpress.Data.CustomSummaryProcess.Calculate) {
        if (ASPxGridView1.Selection.IsRowSelectedByKey(e.GetValue(ASPxGridView1.KeyFieldName)))
            totalSum += Convert.ToInt32(e.FieldValue);
    }
    else
    // Finalization. 
    if (e.SummaryProcess == DevExpress.Data.CustomSummaryProcess.Finalize)
        e.TotalValue = totalSum;
}
protected void ASPxGridView1_CustomCallback(object sender, DevExpress.Web.ASPxGridViewCustomCallbackEventArgs e)
{
    if (e.Parameters == "Refresh")
        ASPxGridView1.DataBind();
}

function OnClick(s, e) {
    grid.PerformCallback('Refresh');
}

Result:

Online Demo

ASPxGridView - Export Selected Records