LINQ To XML:按文档定义的元素顺序显示元素InDocumentOrder

这个发生挺有意思的，有时候我们打乱文档元素原有的顺序，比方说对元素顺序进行倒转Reverse

但是有时候又需要取回原有的顺序，这个时候就可以使用InDocumentOrder,下面是例子

XDocument xDocument = new XDocument( 
  new XElement("BookParticipants", 
    new XElement("BookParticipant", 
      new XAttribute("type", "Author"), 
      new XComment("This is a new author."), 
      new XElement("FirstName", "Joe"), 
      new XElement("LastName", "Rattz")), 
    new XElement("BookParticipant", 
      new XAttribute("type", "Editor"), 
      new XElement("FirstName", "Ewan"), 
      new XElement("LastName", "Buckingham")))); 
 
IEnumerable<XNode> nodes = 
  xDocument.Element("BookParticipants").Elements("BookParticipant"). 
    Nodes().Reverse(); 
 
//  First, we will display the source nodes. 
foreach (XNode node in nodes) 
{ 
  Console.WriteLine("Source node: {0}", node); 
} 
 
//  Now, we will display each source node's child nodes. 
foreach (XNode node in nodes.InDocumentOrder()) 
{ 
  Console.WriteLine("Ordered node: {0}", node); 
} 

这里面已经对结点顺序进行了倒转

IEnumerable<XNode> nodes =

xDocument.Element("BookParticipants").Elements("BookParticipant").

Nodes().Reverse();

下面的输出可以看到InDocumentOrder所起的作用

Source node: <LastName>Buckingham</LastName>

Source node: <FirstName>Ewan</FirstName>

Source node: <LastName>Rattz</LastName>

Source node: <FirstName>Joe</FirstName>

Source node: <!--This is a new author.-->

Ordered node: <!--This is a new author.-->

Ordered node: <FirstName>Joe</FirstName>

Ordered node: <LastName>Rattz</LastName>

Ordered node: <FirstName>Ewan</FirstName>

Ordered node: <LastName>Buckingham</LastName>