create nested xml document in c#

Question

i am a newbie in XmlDocument.i want to create nested xml document in c#.through some reaserach i fount that XmlDocument are recommended way to create xml if size is small.

i am having some trouble while creating nested tags

code:

XmlDocument doc = new XmlDocument();
XmlDeclaration xDeclare = doc.CreateXmlDeclaration("1.0", "UTF-8", null);
XmlElement root = doc.DocumentElement;
doc.InsertBefore(xDeclare, root);
XmlElement el = (XmlElement)doc.AppendChild(doc.CreateElement("FIXML"));
el.AppendChild(doc.CreateElement("Header")).InnerText = "";
el.AppendChild(doc.CreateElement("RequestHeader")).InnerText = "";
el.AppendChild(doc.CreateElement("MessageKey")).InnerText = "";
el.AppendChild(doc.CreateElement("RequestUUID")).InnerText = "938692349";
Console.WriteLine(doc.OuterXml);

its giving output as

<?xml version="1.0" encoding="UTF-8"?>
<FIXML>
    <Header></Header>
    <RequestHeader></RequestHeader>
    <MessageKey></MessageKey>
    <RequestUUID>938692349</RequestUUID>
</FIXML>

but it should be like

<?xml version="1.0" encoding="UTF-8"?>
<FIXML>
    <Header>
        <RequestHeader>
            <MessageKey>
                <RequestUUID>938692349</RequestUUID>
            </MessageKey>
        </RequestHeader>
    </Header>
</FIXML>

Answer 1

Much easier with the newer XML API (XDocument)

var doc = 
    new XElement("FIXML",        // you can optionally add an XDocument as outer element
      new XElement ("Header", 
          .... // more child elements, values and/or attributes
          new XElement("RequestUUID", 938692349)
      ));


doc.Save(fileName);

Answer 2

You are appending all your children to the root element. You probably need something along the lines of:

XmlDocument doc = new XmlDocument();
XmlDeclaration xDeclare = doc.CreateXmlDeclaration("1.0", "UTF-8", null);
XmlElement documentRoot = doc.DocumentElement;
doc.InsertBefore(xDeclare, documentRoot);
XmlElement rootEl = (XmlElement)doc.AppendChild(doc.CreateElement("FIXML"));
XmlElement child1 = (XmlElement)rootEl.AppendChild(doc.CreateElement("Header"));
XmlElement child2 = (XmlElement)child1.AppendChild(doc.CreateElement("RequestHeader"));
...

Answer 3

The problem is in your following statement....

el.AppendChild(doc.CreateElement("Header")).InnerText = "";
el.AppendChild(doc.CreateElement("RequestHeader")).InnerText = "";
el.AppendChild(doc.CreateElement("MessageKey")).InnerText = "";
el.AppendChild(doc.CreateElement("RequestUUID")).InnerText = "938692349";

you are appending everything to el. This is why you are getting the wrong out put instead as per your output you should do like below...

XmlElement header = doc.CreateElement("Header")).InnerText = "";
XmlElement RequestHeader = doc.CreateElement("RequestHeader")).InnerText = "";
header.AppendChild(RequestHeader);

This code will help to achieve expected output.

Answer 4

If you want to do this dynamically using XElement. Assuming your input is present in some kind of collection or Array. You can try the below method.

List<string> xmlList = new List<string>();
        xmlList.Add("FIXML");
        xmlList.Add("Header");
        xmlList.Add("RequestHeader");
        xmlList.Add("RequestUUID");

        XElement parentNode = null;
        string lastParent = null;

        foreach (var item in xmlList)
        {
            if (parentNode == null)
            {
                parentNode = new XElement(item);
                lastParent = XmlConvert.EncodeName(item);
            }
            else
            {
                var ln = parentNode.DescendantsAndSelf().FirstOrDefault(x => x.Name.LocalName == lastParent);
                ln.Add(new XElement(XmlConvert.EncodeName(item)));
                lastParent = XmlConvert.EncodeName(item);


            }
        }

        Console.WriteLine(parentNode);
        Console.ReadLine();