Customization

This is the answer

public PXAction<PX.Objects.CA.CABatch> Attach;

        [PXButton(CommitChanges = true)]
        [PXUIField(DisplayName = "Attach")]
        protected virtual IEnumerable attach(PXAdapter adapter)
        {
            // Use your favorite library to create XML file
            XmlDocument xmlDoc = new XmlDocument();
            xmlDoc.AppendChild(xmlDoc.CreateXmlDeclaration("1.0", "UTF-8", null));

            // Create root node of XML file
            XmlNode rootNode = xmlDoc.CreateElement("GridData");

            // Iterate rows of the DataView
            foreach (CABatchDetail dacRecord in Base.BatchPayments.Select())
            {
                // Create an XML Element to represent the DAC row
                XmlNode xmlDACRecord = xmlDoc.CreateElement("DACRecord");

                // Add desired DAC fields as child XML Elements of the DAC row XML element
                XmlNode xmlDACField1 = xmlDoc.CreateElement("DACField1");
                xmlDACField1.AppendChild(xmlDoc.CreateTextNode(dacRecord.OrigRefNbr.ToString()));
                xmlDACRecord.AppendChild(xmlDACField1);

                XmlNode xmlDACField2 = xmlDoc.CreateElement("DACField2");
                xmlDACField2.AppendChild(xmlDoc.CreateTextNode(dacRecord.OrigDocType.ToString()));
                xmlDACRecord.AppendChild(xmlDACField2);

                // Adding XML DAC Record to XML root node
                rootNode.AppendChild(xmlDACRecord);
            }

            // Adding XML root node to XML document
            xmlDoc.AppendChild(rootNode);

            // Redirect browser to XML file created in memory on server
            throw new PXRedirectToFileException(new PX.SM.FileInfo(Guid.NewGuid(),
                                                                   "filename.xml",
                                                                   null,
                                                                   System.Text.Encoding.UTF8.GetBytes(xmlDoc.OuterXml)),
                                                true);

            return adapter.Get();