Serializing the dictionary <string, object> when the dictionary was initialized using string-insensitive string comparison

Question

I am serializing a dictionary in XML. When I create a new dictionary, I use the constructor to provide EqualityComparer without a shell, for example

var tabs = new Dictionary<string,Tab>(StringComparer.OrdinalIgnoreCase); 

Then I serialize to XML and when I deserialize the casing information, it is lost - deserialization is done using a dictionary with the GenericEqualityComparer, which seems to be case sensitive because it does not find my keys if they are not set correctly.

Any ideas how I can change it?

One way is to create a new dictionary and copy the data from deserialized to a new one, but it seems unpleasant.

UPDATE:

Deserialization worked all the time, until it simply deserializes a serialized dictionary that does not use case-insensitive keys.

Answer 1

I know this question is pretty old, but recently I found how to do it.

Using .Net4 (e.g. @mare said), you can create some really nice extension methods to make this easy. Check out fooobar.com/questions/76824 / ... for a nice and simple implementation.

After a lot of digging, it worked like a charm for me.

Answer 2

Edit:

In the comments, it looks like this approach may be deprecated in .NET 4.

Edit end

Dictionaries happen to require a little help for serialization and deserialization.

Here is a good example of an XML Serializable dictionary:

http://weblogs.asp.net/pwelter34/archive/2006/05/03/444961.aspx

You can make case insensitive by changing the class declaration and adding a constructor and changing the string.

** EDIT: Fixed syntax error below. / EDIT **

 public class SerializableDictionary<TValue> : Dictionary<string, TValue>, IXmlSerializable { public SerializableDictionary() : base(StringComparer.InvariantCultureIgnoreCase) { } // ... } 

Change the line this.Add(key, value); on this[key] = value; .

In any case, you may need a ton of some details, but this should help you well.

Answer 3

You just need to wrap your new dictionary in the constructor:

 Dictionary<string, Tab> tabs ; tabs = new Dictionary<string, Tab>((Dictionary<string, Tab>)serializer.ReadObject(reader),StringComparer.OrdinalIgnoreCase); 

Answer 4

An old question that I understand, but just broke through the source to Dictionary and noticed that it should actually serialize Comparer:

 info.AddValue(ComparerName, comparer, typeof(IEqualityComparer<tkey>)); 

Then, in the implementation of IDeserializationCallback.OnDeserialization it retrieves Comparar:

 comparer = (IEqualityComparer<tkey>)m_siInfo.GetValue(ComparerName, typeof(IEqualityComparer<tkey>)); 

Classes that implement the IDeserializationCallback interface define the method that must be executed after the instance has been deserialized, but before it is returned to your code.

Reference: Dictionary.cs GetObjectData and OnDeserialization Methods