Facing a problem in XML structure generated from data

Using System.Xml.Serialization create your order objects:

public class XMLEntities
{   
  [XmlRoot(ElementName = "CompleteBooking")]
  public class CompleteBooking
  {
    [XmlElement(ElementName = "Booking")]
    public Booking Bookings { get; set; }

    [XmlElement(ElementName = "BookingDetail")]
    public List<BookingDetail> BookingDetail { get; set; }
  }

  public class Booking
  {
    [XmlElement("ID")]
    public int ID { get; set; }

    [XmlElement("BookingNumber")]
    public int BookingNumber { get; set; }

    [XmlElement("ReferenceNumber")]
    public string ReferenceNumber { get; set; }

    [XmlElement("Name")]
    public string Name { get; set; }

    [XmlElement("Address")]
    public string Address { get; set; }
  }

  public class BookingDetail
  {
    [XmlElement("ID")]
    public int ID { get; set; }

    [XmlElement("BookingID")]
    public int BookingID { get; set; }

    [XmlElement("OrderItem")]
    public string OrderItem { get; set; }
  }
}

      

        
        
        
      

    

Now for the serializer object (used to serialize objects to string):

 public class XMLEntitiesSerializer
 {
   public string Serialize(XMLEntities.CompleteBooking completeBooking)
   {
     var serializedXml = string.Empty;

     var serializer = new XmlSerializer(typeof (XMLEntities.CompleteBooking));
     var stringWriter = new System.IO.StringWriter();

     try
     {
       serializer.Serialize(stringWriter, completeBooking);
       serializedXml = stringWriter.ToString();
     }
     catch(Exception ex)
     {
       //Log the stuff
     }
     finally
     {
       stringWriter.Close();
     }

     return serializedXml;
   }
 }

      

        
        
        
      

    

Now you just create correctly defined objects and serialize in some function. For example, in the main method of the console application:

public static void Main(string[] args)
{
  //Create new booking objects
  var booking1 = new XMLEntities.Booking()
                  {
                    ID = 32,
                    BookingNumber = 1212001,
                    ReferenceNumber = "ABCED11212280007",
                    Name = "Customer Name1",
                    Address = "Customer Address"
                  };
  var booking2 = new XMLEntities.Booking()
                   {
                     ID = 33,
                     BookingNumber = 12120002,
                     ReferenceNumber = "ABCED11212280008",
                     Name = "Customer Name2",
                     Address = "Customer Address2"
                   };

  //Create the booking details objects

  var booking1Detail1 = new XMLEntities.BookingDetail()
                         {
                           ID = 206,
                           BookingID = 32,
                           OrderItem = "Item1"
                         };
  var booking1Detail2 = new XMLEntities.BookingDetail()
                          {
                            ID = 207,
                            BookingID = 32,
                            OrderItem = "Item2"
                          };

  var booking2Detail1 = new XMLEntities.BookingDetail()
                          {
                            ID = 208,
                            BookingID = 33,
                            OrderItem = "Item1"
                          };
  var booking2Detail2 = new XMLEntities.BookingDetail()
                          {
                            ID = 209,
                            BookingID = 32,
                            OrderItem = "Item2"
                          };
  var booking2Detail3 = new XMLEntities.BookingDetail()
                          {
                            ID = 210,
                            BookingID = 32,
                            OrderItem = "Item3"
                          };

  //Smash them together so we can serialize as one

  var completeBooking1 = new XMLEntities.CompleteBooking()
                          {
                            Bookings = booking1,
                            BookingDetail = new List<XMLEntities.BookingDetail>()
                                              {
                                                booking1Detail1,
                                                booking1Detail2
                                              }
                          };
  var completeBooking2 = new XMLEntities.CompleteBooking()
                           {
                             Bookings = booking2,
                             BookingDetail = new List<XMLEntities.BookingDetail>()
                                               {
                                                 booking2Detail1,
                                                 booking2Detail2,
                                                 booking2Detail3
                                               }
                           };

  //Serialize the data for each of the booking objects

  var serializedXML = new XMLEntitiesSerializer();
  var xml = string.Empty;

  var booking1XmlString = serializedXML.Serialize(completeBooking1);
  var booking2XmlString = serializedXML.Serialize(completeBooking2);

  Console.ReadLine();
}

      

        
        
        
      

    

Obviously, you can use this in a refactored function (which would make life easier), but it gives you the general conclusion you are looking for.

Let's say we have the following classes for data:

class Booking
{
    public int ID { get; set;}
    public int BookingNumber { get; set;}
    public string ReferenceNo { get; set;}
    public string Name { get; set;}
    public string Address { get; set;}
}

class BookingDetails
{
    public int ID { get; set;}
    public int BookingId { get; set;}
    public string OrderItem { get; set;}
}

      

        
        
        
      

    

And the following test data:

    static private IList<Booking> _bookings = new List<Booking>() {
        new Booking() { ID = 32, BookingNumber = 12120001, ReferenceNo = "ABCED11212280007", Name = "Customer Name1", Address = "Customer Address" },
        new Booking() { ID = 33, BookingNumber = 12120002, ReferenceNo = "ABCED11212280008", Name = "Customer Name2", Address = "Customer Address2" }
    };

    static private IList<BookingDetails> _details = new List<BookingDetails>() {
        new BookingDetails() { ID = 206, BookingId = 32, OrderItem = "Item1" },
        new BookingDetails() { ID = 207, BookingId = 32, OrderItem = "Item2" },
        new BookingDetails() { ID = 208, BookingId = 33, OrderItem = "Item1" },
        new BookingDetails() { ID = 209, BookingId = 33, OrderItem = "Item2" },
        new BookingDetails() { ID = 210, BookingId = 33, OrderItem = "Item3" }
    };

      

        
        
        
      

    

We can easily get the output XML in this format with the following Linq to XML query:

var bookings = _bookings.Join(_details, b => b.ID, d => d.BookingId, (b, d) => new { b, d })
                        .GroupBy(g => g.b, g => g.d)
                        .Select(g => new XElement("CompleteBooking",
                                        new XElement("Booking", 
                                            new XElement("ID", g.Key.ID),
                                            new XElement("BookingNumber", g.Key.BookingNumber),
                                            new XElement("ReferenceNo", g.Key.ReferenceNo),
                                            new XElement("Name", g.Key.Name),
                                            new XElement("Address", g.Key.Address)),
                                        g.Select(d => new XElement("BookingDetail",
                                                            new XElement("ID", d.ID),
                                                            new XElement("BookingID", d.BookingId),
                                                            new XElement("OrderItem", d.OrderItem))).ToArray())).ToArray();

      

        
        
        
      

    

This will give us an array of XElement objects. To get the xml string use the method String.Join<XElement>

:

var xmlString = String.Join<XElement>(Environment.NewLine, bookings);

      

        
        
        
      

    

However , I would suggest a slightly different XML schema:

<Bookings>
  <Booking>
    <ID>32</ID>
    <BookingNumber>12120001</BookingNumber>
    <ReferenceNo>ABCED11212280007</ReferenceNo>
    <Name>Customer Name1</Name>
    <Address>Customer Address</Address>
    <Details>
      <Detail>
        <ID>206</ID>
        <OrderItem>Item1</OrderItem>
      </Detail>
      <Detail>
        <ID>207</ID>
        <OrderItem>Item2</OrderItem>
      </Detail>
    </Details>
  </Booking>
  <Booking>
    <ID>33</ID>
    <BookingNumber>12120002</BookingNumber>
    <ReferenceNo>ABCED11212280008</ReferenceNo>
    <Name>Customer Name2</Name>
    <Address>Customer Address2</Address>
    <Details>
      <Detail>
        <ID>208</ID>
        <OrderItem>Item1</OrderItem>
      </Detail>
      <Detail>
        <ID>209</ID>
        <OrderItem>Item2</OrderItem>
      </Detail>
      <Detail>
        <ID>210</ID>
        <OrderItem>Item3</OrderItem>
      </Detail>
    </Details>
  </Booking>
</Bookings>

      

        
        
        
      

    

There is no redundancy in data with this format. To use it in the following query:

var bookings = _bookings.Join(_details, b => b.ID, d => d.BookingId, (b, d) => new { b, d })
                        .GroupBy(g => g.b, g => g.d)
                        .Select(g => new XElement("Booking", 
                                        new XElement("ID", g.Key.ID),
                                        new XElement("BookingNumber", g.Key.BookingNumber),
                                        new XElement("ReferenceNo", g.Key.ReferenceNo),
                                        new XElement("Name", g.Key.Name),
                                        new XElement("Address", g.Key.Address),
                                        new XElement("Details",
                                            g.Select(d => new XElement("Detail",
                                                              new XElement("ID", d.ID),
                                                              new XElement("OrderItem", d.OrderItem))).ToArray()))).ToArray();

var data = new XDocument(new XElement("Bookings", bookings));

      

        
        
        
      

    

You can create a custom structure using LINQ to XML. Use nested XElement constructors. See for example How to create XML of this structure and Generate XML dynamically using C #