Question

I have the following xml which represents 2 types of plugins, FilePlugin and RegsitryPlugin:

<Client>
  <Plugin Type="FilePlugin">
    <Message>i am a file plugin</Message>
    <Path>c:\</Path>
  </Plugin>
  <Plugin Type="RegsitryPlugin">
    <Message>i am a registry plugin</Message>
    <Key>HKLM\Software\Microsoft</Key>
    <Name>Version</Name>
    <Value>3.5</Value>
  </Plugin>
</Client>

I would like to deserialize the xml into objects.
As you can see, the ‘Message’ element is repeating itself both for the FilePlugin and the RegistryPlugin and i am using inheritance for this:

    abstract class Plugin
    {
        private string _message;
        protected Plugin(MISSING conf)
        {
            // here i need to set my private members like:
            // Message = MISSING.Message;
        }
    }

    class FilePlugin : Plugin
    {
        private string _path;
        public FilePlugin(MISSING config)
            : base(config)
        {
            // Here i need to set my private members like:
            // _path = config.Path;
        }
    }

    class RegistryPlugin : Plugin
    {
        private string _key;
        private string _name;
        private string _value;
        public RegistryPlugin(MISSING config)
            : base(config)
        {
            // Here i need to set my private members like:
            // _key = config.Key;
            // _key = config.Name;
            // _key = config.Value;
        }
    }
}

I need somehow to deserialize the xml, and than to decide according the PluginType Element which Instance to create:
i.e:
if it is written in the xml the Type=FilePlugin than i need to create

Plugin p1 = new FilePlugin(conf);

if it is written in the xml the Type=RegistryPlugin than i need to create

Plugin p2 = new RegistryPlugin(conf);

Please follow my comments in my code in order to understand the missing parts.
Thanks

Answer 1

Creating your own deserializer isn’t also hard. Here is my solution to this:

using System;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using System.Xml.Linq;
using System.Reflection;
using System.Text;

namespace WindowsFormsApplication1
{
    public abstract class Plugin
    {
        public string Type { get; set; }
        public string Message { get; set; }
    }

    public class FilePlugin : Plugin
    {
        public string Path { get; set; }
    }

    public class RegsitryPlugin : Plugin
    {
        public string Key { get; set; }
        public string Name { get; set; }
        public string Value { get; set; }
    }

    static class MyProgram
    {
        [STAThread]
        static void Main(string[] args)
        {
            string xmlstr =@"
                <Client>
                  <Plugin Type=""FilePlugin"">
                    <Message>i am a file plugin</Message>
                    <Path>c:\</Path>
                  </Plugin>
                  <Plugin Type=""RegsitryPlugin"">
                    <Message>i am a registry plugin</Message>
                    <Key>HKLM\Software\Microsoft</Key>
                    <Name>Version</Name>
                    <Value>3.5</Value>
                  </Plugin>
                </Client>
              ";

            Assembly asm = Assembly.GetExecutingAssembly();
            XDocument xDoc = XDocument.Load(new StringReader(xmlstr));
            Plugin[]  plugins = xDoc.Descendants("Plugin")
                .Select(plugin =>
                {
                    string typeName = plugin.Attribute("Type").Value;
                    var type = asm.GetTypes().Where(t => t.Name == typeName).First();
                    Plugin p = Activator.CreateInstance(type) as Plugin;
                    p.Type = typeName;
                    foreach (var prop in plugin.Descendants())
                    {
                        type.GetProperty(prop.Name.LocalName).SetValue(p, prop.Value, null);
                    }

                    return p;
                }).ToArray();

            //
            //"plugins" ready to use
            //
        }
    }
}