The .NET Universe revealed! - techniques for the .NET Developer

here I iterate trough every private variable (in the FieldInfo class) and write a node with the value to the XmlWriter.

Sidenotes:

• (The GetFields() method is used to get the FieldInfo array from a static hashtable if it was requested before for performance reasons or from the class itself by reflection)
• You can see that I do something else for a field of a valuetype compared to a field of a referencetype.  A valuetype can be written in the node itself.  A reference type, a normal class, has to be serialized too.  So here you see the serialisation code for serializing classes.  But there is one thing different with normal serialisation, that is the use of the PrivateFieldXmlTextWriter.  Instead of using a normal TextWriter I use my own that overrides the method to write out the xml version code (<?xml version="1.0"?>).  This is because this should only be written out on the beginning of the xml document.

I do exactly the same the other way around for reading back into a class.  the class must have a public default constructor to be able to instantiate a new class and then fill it afterwards.  In .NET 2.0 this constructor may also be internal (if I'm right).

        /// <summary>
        /// Converts an XML document into an object using the specified reader.
        /// </summary>
        /// <param name="reader">The <see cref="T:System.Xml.XmlReader"/> used to read the XML document.</param>
        public void ReadXml(System.Xml.XmlReader reader) {
            XmlDocument doc = new XmlDocument();
            doc.LoadXml(reader.ReadOuterXml());
            foreach(FieldInfo fi in GetFields()){
                string nodePath = "/" + this.GetType().Name + "/" + fi.Name.Trim('_');
                XmlNode node = doc.SelectSingleNode(nodePath) ;
                string val = node.InnerText;
                fi.SetValue(this,ConvertXmlToDatatype(fi.FieldType,val));
            }
        }

What I do here is using XPath queries to get the content from the node and I made a method to return the object as the correct datatype.  After that it is inserted via reflection into the variable it came from.

One thing you see al the time is the Trimming of the underscore of a variable.  I do this so that you can make all your variables start with an underscore but still having valid xml without an underscore as the first character in the XmlNode.  This wil make a variable like _id to be converted in Xml as <id>1</id>.

I hope you find this class very usefull and that it will solve many of your Xml Serialization problems.

Good luck.