protected void RadGrid1_ItemCommand(object sender, GridCommandEventArgs e)
{
    if (e.CommandName == RadGrid.ExportToExcelCommandName)
    {
        //prevent the default exporting
        e.Canceled = true;

        //generate Workbook out of the Grid for exporting
        DPL.Workbook workbook = RadGrid1.MasterTableView.GenerateXlsxOutput<DPL.Workbook>() as DPL.Workbook;
        DPL.Worksheet worksheet = workbook.ActiveSheet as DPL.Worksheet;

        //remove the command item from the exported workbook
        var commandRowIndex = 0;
        DPL.RowSelection commandRow = worksheet.Rows[commandRowIndex];
        commandRow.Remove();
        //alternative approach to remove the command item
        //RadGrid1.MasterTableView.CommandItemDisplay = GridCommandItemDisplay.None;
        //RadGrid1.Rebind();

        //remove the filter item from the exported workbook
        var filterRowIndex = 1;
        DPL.RowSelection filterRow = worksheet.Rows[filterRowIndex];
        filterRow.Remove();

        //export and send to the browser as response
        byte[] data;
        using (MemoryStream ms = new MemoryStream())
        {
            var provider = new XlsxFormatProvider();
            provider.Export(workbook, ms);
            data = ms.ToArray();
        }
        Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
        Response.Headers.Remove("Content-Disposition");
        Response.AppendHeader("Content-Disposition", "attachment; filename=" + RadGrid1.ExportSettings.FileName + ".xlsx");
        Response.BinaryWrite(data);
        Response.End();
    }
}