How to create an XML document from a .NET object?

Question

I have the following variable that accepts a file name:

var xtr = new XmlTextReader(xmlFileName) { WhitespaceHandling = WhitespaceHandling.None };
var xd = new XmlDocument();
xd.Load(xtr);

I would like to change it so that I can pass in an object. I don't want to have to serialize the object to file first.

Is this possible?

Update:

My original intentions were to take an xml document, merge some xslt (stored in a file), then output and return html... like this:

public string TransformXml(string xmlFileName, string xslFileName)
{
     var xtr = new XmlTextReader(xmlFileName) { WhitespaceHandling = WhitespaceHandling.None };
     var xd = new XmlDocument();
     xd.Load(xtr);

     var xslt = new System.Xml.Xsl.XslCompiledTransform();
     xslt.Load(xslFileName);
     var stm = new MemoryStream();
     xslt.Transform(xd, null, stm);
     stm.Position = 1;
     var sr = new StreamReader(stm);
     xtr.Close();
     return sr.ReadToEnd();
}

In the above code I am reading in the xml from a file. Now what I would like to do is just work with the object, before it was serialized to the file.

So let me illustrate my problem using code

public string TransformXMLFromObject(myObjType myobj , string xsltFileName)
{
     // Notice the xslt stays the same.
     // Its in these next few lines that I can't figure out how to load the xml document (xd) from an object, and not from a file....

     var xtr = new XmlTextReader(xmlFileName) { WhitespaceHandling = WhitespaceHandling.None };
     var xd = new XmlDocument();
     xd.Load(xtr);
}

I don't follow what you are wanting to do, can you post a better example? — Kyle Rosendo
– Kyle Rosendo, Commented Mar 30, 2010 at 21:05
change what so that you can pass in an object? The XmlTextReader? you want to pass an object to the XmlTextReader? And what do you expect to get out ? — Cheeso
– Cheeso, Commented Mar 30, 2010 at 21:09
@JL: you should not be using new XmlTextReader(). You should be using XmlReader.Create() instead. — John Saunders
– John Saunders, Commented Mar 30, 2010 at 21:14
@Cheeso, I want to load xd (the XMLDocument) from an object, not from file, the XMLTextReader is not important to me. — JL.
– JL., Commented Mar 30, 2010 at 21:14

marc_s · Accepted Answer · 2010-03-30 21:17:00Z

36

You want to turn an arbitrary .NET object into a serialized XML string? Nothing simpler than that!! :-)

public string SerializeToXml(object input)
{
   XmlSerializer ser = new XmlSerializer(input.GetType(), "http://schemas.yournamespace.com");
   string result = string.Empty;

   using(MemoryStream memStm = new MemoryStream())
   {
     ser.Serialize(memStm, input);

     memStm.Position = 0;
     result = new StreamReader(memStm).ReadToEnd();
   } 

   return result;
}

That should to it :-) Of course you might want to make the default XML namespace configurable as a parameter, too.

Or do you want to be able to create an XmlDocument on top of an existing object?

public XmlDocument SerializeToXmlDocument(object input)
{
   XmlSerializer ser = new XmlSerializer(input.GetType(), "http://schemas.yournamespace.com");

   XmlDocument xd = null;

   using(MemoryStream memStm = new MemoryStream())
   {
     ser.Serialize(memStm, input);

     memStm.Position = 0;

     XmlReaderSettings settings = new XmlReaderSettings();
     settings.IgnoreWhitespace = true;

     using(var xtr = XmlReader.Create(memStm, settings))
     {  
        xd = new XmlDocument();
        xd.Load(xtr);
     }
   }

   return xd;
}

edited Mar 30, 2010 at 21:17

answered Mar 30, 2010 at 21:11

marc_s

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10 Comments

John Saunders Over a year ago

@marc_s: ick! No using blocks! new XmlTextReader()! -1!

marc_s Over a year ago

@John: I was just fixing the new XmlTextReader().... you're too quick to downvote......

marc_s Over a year ago

@John: but explain to me in simple and easy to understand words the benefit of XmlReader.Create() vs. new XmlTextReader() - nobody has made a compelling point so far.....

Darin Dimitrov Over a year ago

@marc_s, quote from the doc:

Although the Microsoft .NET Framework includes concrete implementations of the XmlReader class, such as the XmlTextReader, XmlNodeReader, and the XmlValidatingReader classes, in the .NET Framework version 2.0, we recommend that you create XmlReader instances using the Create method

(msdn.microsoft.com/en-us/library/9khb6435.aspx). I guess the only compelling reason might be that if in .NET 7.9 they introduce the HyperXmlReader class you won't need to change your code to benefit from it :-)

Thomas Levesque Over a year ago

@marc_s: in your second piece of code, it doesn't change anything. But in the first one, you're returning a string, so using a MemoryStream and then reading it with a StreamReader to obtain a string seems a bit overcomplicated... with a StringWriter, you get a string directly

|

John Saunders · Accepted Answer · 2010-03-31 02:02:55Z

31

You can serialize directly into the XmlDocument:

XmlDocument doc = new XmlDocument();
XPathNavigator nav = doc.CreateNavigator();
using (XmlWriter w = nav.AppendChild())
{
    XmlSerializer ser = new XmlSerializer(typeof(MyType));
    ser.Serialize(w, myObject);
}

edited Mar 31, 2010 at 2:02

answered Mar 30, 2010 at 21:15

John Saunders

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9 Comments

JL. Over a year ago

I think the ser.Serializer doesn't accept the object as a parameter?

Thomas Levesque Over a year ago

uh, nice... and no intermediate string involved :)

JL. Over a year ago

If I wasn't clear enough, the code above doesn't compile because ser.Serialize has some invalid parameters. Otherwise it looks like an elegant solution.

John Saunders Over a year ago

But since it's not a proper benchmark, it may give a false idea of the performance.

John Saunders Over a year ago

@randomuser: no intermediate Stream or TextReader objects. If you only need those objects to construct the XmlDocument, then why bother with them?

|

lauxjpn · Accepted Answer · 2023-11-30 17:28:44Z

16

Expanding on @JohnSaunders solution I wrote the following generic function:

public static XmlDocument SerializeToXml<T>(
            T source,
            XmlSerializerNamespaces namespaces = null)
{
    var document = new XmlDocument();
    var navigator = document.CreateNavigator();

    using var writer = navigator.AppendChild();
    var serializer = new XmlSerializer(typeof(T));
    serializer.Serialize(writer, source, namespaces);
    
    return document;
}

edited Nov 30, 2023 at 17:28

lauxjpn

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answered Aug 8, 2017 at 13:02

Jasper Risseeuw

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