public class GridXlExportOptions :
    GridExportOptions,
    IGridXlExportOptions

<div class="grid-container">
    <DxGrid @ref="Grid"
            Data="@Data"
            ShowSearchBox="true"
            SearchText="Manager"
            ShowGroupPanel="true"
            AutoExpandAllGroupRows="true"
            GroupFooterDisplayMode="GridGroupFooterDisplayMode.IfExpanded"
            SelectionMode="GridSelectionMode.Multiple"
            SelectAllCheckboxMode="GridSelectAllCheckboxMode.AllPages"
            ColumnResizeMode="GridColumnResizeMode.NextColumn"
            TextWrapEnabled="false"
            SizeMode="Params.SizeMode"
            HighlightRowOnHover="true">
        <Columns>
            <DxGridSelectionColumn Width="60px" AllowSelectAll="true" />
            <DxGridDataColumn FieldName="ContactName" Width="15%" />
            <DxGridDataColumn FieldName="ContactTitle" Width="15%" />
            <DxGridDataColumn FieldName="CompanyName" Width="20%" />
            <DxGridDataColumn FieldName="Country" Width="15%" GroupIndex="0" />
            <DxGridDataColumn FieldName="FullAddress" UnboundType="GridUnboundColumnType.String" UnboundExpression="[City] + ' - ' + [PostalCode] + ' - ' + [Address]" />
        </Columns>
        <TotalSummary>
            <DxGridSummaryItem FieldName="ContactName" SummaryType="GridSummaryItemType.Count" />
        </TotalSummary>
        <GroupSummary>
            <DxGridSummaryItem FieldName="ContactName" SummaryType="GridSummaryItemType.Count" FooterColumnName="ContactName" />
        </GroupSummary>
        <ToolbarTemplate>
            <DxToolbar>
                <DxToolbarItem Text="Export to XLSX" Click="ExportXlsx_Click" BeginGroup="true" />
                <DxToolbarItem Text="Export to XLS" Click="ExportXls_Click" BeginGroup="true" />
                <DxToolbarItem Text="Export to CSV" Click="ExportCsv_Click" BeginGroup="true" />
                <DxToolbarItem Context="itemCtx" Alignment="ToolbarItemAlignment.Right" BeginGroup="true">
                    <Template>
                        <DxCheckBox @bind-Checked="@ExportSelectedRowsOnly">Export Selected Rows Only</DxCheckBox>
                    </Template>
                </DxToolbarItem>
            </DxToolbar>
        </ToolbarTemplate>
    </DxGrid>
</div>

@code {
    IEnumerable<object> Data { get; set; }
    IGrid Grid { get; set; }
    bool ExportSelectedRowsOnly { get; set; }

    protected override async Task OnInitializedAsync() {
        Data = await NwindDataService.GetCustomersAsync();
    }
    async Task ExportXlsx_Click() {
        await Grid.ExportToXlsxAsync("ExportResult", new GridXlExportOptions() {
            ExportSelectedRowsOnly = ExportSelectedRowsOnly,
            SelectedRowsExportMode = GridSelectedRowsExportMode.KeepGrouping,
            CustomizeCell = OnCustomizeXlCell
        });
    }
    async Task ExportXls_Click() {
        await Grid.ExportToXlsAsync("ExportResult", new GridXlExportOptions() {
            ExportSelectedRowsOnly = ExportSelectedRowsOnly,
            SelectedRowsExportMode = GridSelectedRowsExportMode.KeepGrouping,
            CustomizeCell = OnCustomizeXlCell
        });
    }
    async Task ExportCsv_Click() {
        await Grid.ExportToCsvAsync("ExportResult", new GridCsvExportOptions() {
            ExportSelectedRowsOnly = ExportSelectedRowsOnly
        });
    }
    void OnCustomizeXlCell (GridExportCustomizeCellEventArgs args) {
        if(args.ColumnFieldName == "ContactName" && args.AreaType == SheetAreaType.DataArea)
            args.Formatting.Font = new XlCellFont() { Italic = true };
        args.Handled = true;
    }
}