public event EventHandler<WebCustomExportCellEventArgs> CustomExportCell

Public Event CustomExportCell As EventHandler(Of WebCustomExportCellEventArgs)

using System;
using System.Drawing;
using DevExpress.XtraPivotGrid.Web;
using DevExpress.XtraPrinting;

public partial class _Default : System.Web.UI.Page 
{
    static double maxPrice = 99;
    protected void ASPxPivotGridExporter1_CustomExportCell(
                          object sender,
                          WebCustomExportCellEventArgs e) {
        if (e.DataField.FieldName == "UnitPrice" &&
                Convert.ToDouble(e.Value) > 0 &&
                Convert.ToDouble(e.Value) < maxPrice) {
            // Specifies the cell's display text.
            ((TextBrick)e.Brick).Text = string.Format(
                     "Custom text: {0}",
                     ((TextBrick)e.Brick).Text);
            // Specifies the appearance settings used to paint the cell in a document.
            e.Appearance.BackColor = Color.Green;
            e.Appearance.ForeColor = Color.White;
        }
    }
    protected void ASPxButton1_Click(object sender, EventArgs e) {
        ASPxPivotGridExporter1.ExportToXls(@"C:\pivotdata.xls", TextExportMode.Text);
    }
}

<dx:ASPxButton ID="ASPxButton1" runat="server" OnClick="ASPxButton1_Click" Text="Export">
</dx:ASPxButton>

<dx:ASPxPivotGrid ID="ASPxPivotGrid1" runat="server" ClientIDMode="AutoID" DataSourceID="SqlDataSource1">
    <Fields>
        <dx:PivotGridField ID="fieldProductName" Area="RowArea" AreaIndex="0" FieldName="ProductName">
        </dx:PivotGridField>
        <dx:PivotGridField ID="fieldCountry" Area="ColumnArea" AreaIndex="0" FieldName="Country">
        </dx:PivotGridField>
        <dx:PivotGridField ID="fieldQuantity" Area="DataArea" AreaIndex="1" FieldName="Quantity">
        </dx:PivotGridField>
        <dx:PivotGridField ID="fieldUnitPrice" Area="DataArea" AreaIndex="0" FieldName="UnitPrice">
        </dx:PivotGridField>
    </Fields>
</dx:ASPxPivotGrid>

<dx:ASPxPivotGridExporter ID="ASPxPivotGridExporter1" runat="server" 
   ASPxPivotGridID="ASPxPivotGrid1" OnCustomExportCell="ASPxPivotGridExporter1_CustomExportCell">
</dx:ASPxPivotGridExporter>