Comments on: Serializing an IDictionary object

By: pepz

pepz — Sun, 22 Jun 2008 00:49:36 +0000

I think the function ‘ReadXml’ needs an extra function call to ‘reader.ReadEndElement()’ to fully close out the working node. This should allow it to work within larger object graphs as well.

By: Nikhil Shah

Nikhil Shah — Fri, 21 Mar 2008 07:26:41 +0000

This works very well,
gooood work ,
data gets serialized successfully,
but does not gets deserialize !!!
my problem is smwht like this, I have Four hashtable that stores the key n value pair,
on Form I have 4 combobox n 4 respective textbox ,
I wnt to populate the Key in combobx n Its RESPECTIVE value in textbox
on the selectedindex event of the combx, I where I write a code
I gets an error, tht there is a problem with XML document !!!
this XMl doc is well-formed, No-bugs thr..
this means tht the data is nt deserializing …

If you get this, plz help me out m stuck in this prblm since last 2 days :(

By: Simon

Simon — Wed, 10 Oct 2007 16:16:46 +0000

Hmm, that comment has mangled some of the XML tags that were in the code, the method won’t work as it is shown on this page

By: Simon

Simon — Wed, 10 Oct 2007 16:15:22 +0000

Everything being serialized as a string, and the non-recursive nature of the serialization make this kind of useless. I’ve ended up writing a couple of helper methods that will serialize and deserialize nested IDictionary objects too.

public static StringBuilder Serialize(StringBuilder sb, object obj) { if (typeof(IDictionary).IsAssignableFrom(obj.GetType())) { sb.Append(""); foreach (object key in ((IDictionary)obj).Keys) { sb.Append(""); Serialize(sb, ((IDictionary)obj)[key]); sb.Append(”"); } sb.Append(”"); } else { StringWriter sw = new StringWriter(sb); XmlSerializer xs = new XmlSerializer(obj.GetType()); sb.Append(”"); //need a bodge in here to deal with unnamed datatables xs.Serialize(sw, obj); sb.Append(”"); }


            return sb.Replace(”", “”);

        }
        public static object Deserialize(string s)

        {

            Object obj = new Object();
            XmlDocument xml = new XmlDocument();

            xml.LoadXml(s);
            XmlNode node = xml.ChildNodes[0];

            if (node.Name.Contains(”IDictionary_”))

            {

                obj = Activator.CreateInstance(Type.GetType(XmlConvert.DecodeName(node.Name.Replace(”IDictionary_”, “”))));

                foreach (XmlNode child in node.ChildNodes)

                    ((IDictionary)obj).Add(child.Name.Replace(”Key_”, “”), Deserialize(child.InnerXml));

            }

            else if (node.Name.Contains(”Type_”))

            {

                StringReader sr = new StringReader(”" + node.InnerXml);

                XmlSerializer xs = new XmlSerializer(Type.GetType(XmlConvert.DecodeName(node.Name.Replace(”Type_”, “”))));

                obj = xs.Deserialize(sr);

            }

return obj; }

Use it like this:
Hashtable ht1 = new Hashtable(); ht1["1"] = 1; ht1["2"] = 2;


        Hashtable ht2 = new Hashtable();

        ht2["a"] = “a”;

        ht2["b"] = “b”;
        ht1["3"] = ht2;

Serialize(new StringBuilder(), ht1);

By: Wil

Wil — Thu, 04 Oct 2007 12:41:50 +0000

The serialization loses what I would consider one of the main advantages of the Hashtable and that is the type of the value.

A DateTime value is deserialized as a string and not a DateTime.

By: Daniel

Daniel — Fri, 04 May 2007 08:40:05 +0000

By: Daniel

Daniel — Fri, 04 May 2007 08:39:29 +0000

this is the xml, i don’t know why it wasn’t saved:
This is how the xml must look like:

By: Daniel

Daniel — Fri, 04 May 2007 08:38:01 +0000

hi, i have this class, which has all the collection properties and methods. in it i have a property, Total, which returns the number of elements.
public class PostcodeCollection : CollectionBase {


        // .... other collection's stuff
	[XmlAttribute( "Total" )]

	public int Total

	{

		get { return List.Count; }

		set

		{}

	}

}
this collection is a property in another class:
[XmlRoot("PostCodes" )] public class PostcodeReport { // …other properties

[XmlArray("Updated")] [XmlArrayItem(typeof(PostCodeLine), ElementName="PostCode")] public PostcodeCollection Updated { get { return this.updated; } } }
i serialize the collection, and all is ok, but i want to add the “Total” property to the xml:
This is how the xml must look like:

i don’t know how to apply your example, any thoughts?
thanks,
Daniel

By: Victor Bartel

Victor Bartel — Wed, 31 May 2006 14:37:14 +0000

Greetings,

Thank you for this wonderful article, it helped me so much. I permit me ask you about one problem that I’ve meet. I use .NET 1.1, your class works correctly in web methods, but I have a problem to pass Serialized HashTable from web method to some asp .net application, using web references. When VS environment generate proxy class, it define your DictionarySerializer like a DataSet. For example for next web method:

[Webmethod]
public DictionarySerializer Test()
{
………
return new DictionarySerializer(MyHashTable);
}

VS will generate something like that in a proxy class:

public System.Data.DataSet Test() {
object[] results = this.Invoke(”Test”, new object[0]);
return ((System.Data.DataSet)(results[0]));
}
Without a schema specification the system define serializeble object like a DataSet. What I need to correct this problem, can you help me to do that? Thank you in advance.

Best regards
Victor Bartel

By: Dave J Smith

Dave J Smith — Tue, 09 May 2006 08:14:38 +0000

For those who are struggling to find the correct namespaces:

using System.Xml;
using System.Xml.Schema;
using System.Xml.Serialization;
using System.Collections;
using System.IO;

are required.
Dave.