Friday, July 21, 2017

The magic of LINQ

LINQ is one of my favorite features of the Microsoft .NET Framework.

 It was introduced with VS.NET 2008 / .NET 3.5, and is absolutely incredible.

I often wish we had something like it in Java, where I'm still cobbling together foreach loops to process Object Lists, SAX Parsers to process XML, and HQL/JP-QL to select data. I needed to take a list of Objects and write out XML Export in .NET.

 Here's my code:
            XDocument xmlDocument = new XDocument(new XElement("Agendas",
                from agenda in orgAgendas
                select new XElement("Agenda",
                    new XAttribute("Id", agenda.AgendaId),
                    new XElement("AgendaName", agenda.AgendaName),
                    new XElement("MeetingDateTime", agenda.MeetingDateTime),
                    new XElement("MeetingLocation", agenda.MeetingLocation),
                    new XElement("OriginalFileUrl", agenda.AgendaOrigUrl),
                    new XElement("ConvertedFileUrl", agenda.AgendaPdfUrl),
                    new XElement("Type", agenda.Type),
                    new XElement("TypeDesc", agenda.TypeDesc),
                    new XElement("CreateDate", agenda.CreateDate),
                    new XElement("Published", agenda.Publish),
                    new XElement("Sections",
                    from section in agenda.AgendaSections
                    select new XElement("Section", 
                        new XAttribute("Id", section.SectionId),
                        new XElement("Text", section.SectionText),
                        new XElement("Type", section.Type),
                        new XElement("Owner", userUtils.GetUserNameById(section.OwnerId.GetValueOrDefault())),
                        new XElement("Items",
                        from item in section.AgendaSectionItems
                            select new XElement("Item", 
                            new XAttribute("Id", item.ItemId),
                            new XElement("Text", item.ItemText),
                            new XElement("Owner", userUtils.GetUserNameById(item.OwnerId.GetValueOrDefault())),
                            new XElement("Assignee", userUtils.GetUserNameById(item.AssigneeId.GetValueOrDefault())),
                            new XElement("Completed", item.Completed),
                            new XElement("DueDate", item.DueDate),
                            new XElement("Approved", item.Approved),
                            new XElement("Attachments",
                            from attachment in item.Attachments
                                select new XElement("Attachment",
                                new XAttribute("Id", attachment.AttachmentId),
                                new XElement("Description", attachment.Description),
                                new XElement("OriginalFileUrl", attachment.OriginalUrl),
                                new XElement("ConvertedFileUrl", attachment.ConvertedUrl),
                                new XElement("Confidential", attachment.Confidential)
So elegant ... :-)

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