How to serialize IDictionary

Question

Does anyone know of a creative way to serialize objects that implement IDictionary? ...without implementing a new class?

Answer 1

I take it you mean you have to serialize a dictionary that's part of class you have no control over?

In short, you have to serialize the keys and values separately. To deserialize, step through each item in the key/value arrays and add them back to your dictionary.

Answer 2

You can use the System.Runtime.Serialization.DataContractSerializer, with ReadObject and WriteObject the same way as you would do Deserialize and Serialize. It works like a charm.

Answer 3

If the class implementing IDictionary is serializable (like Dictionary<K,V>) and K and V are serializable then the standard .NET serialization mechanisms should work.

If the class implementing IDictionary is serializable but K and V are then you could use two arrays to serialize the keys and associated values separately:

// before serialization
IDictionary<string,int> dict;
string[] keys = dict.Keys.ToArray();
int[] values = dict.Keys.Select(key => dict[key]).ToArray();

// after deserialization
IDictionary<string,int> dict = new Dictionary<string,int>();
for (int i = 0; i < keys.Length; i++)
    dict.Add(keys[i], values[i]);