I'm currently writing a bidirectional map class, and I'm having some troubles with the serialization/deserialization of the class (question at bottom).
Here's the parts of the class that's relevant.
/// <summary>
/// Represents a dictionary where both keys and values are unique, and the mapping between them is bidirectional.
/// </summary>
/// <typeparam name="TKey"> The type of the keys in the dictionary. </typeparam>
/// <typeparam name="TValue"> The type of the values in the dictionary. </typeparam>
[Serializable]
public class BidirectionalDictionary<TKey, TValue> : IDictionary<TKey, TValue>, IEquatable<BidirectionalDictionary<TKey, TValue>>, ISerializable, IDeserializationCallback
{
/// <summary>
/// A dictionary that maps the keys to values.
/// </summary>
private readonly Dictionary<TKey, TValue> forwardMap;
/// <summary>
/// A dictionary that maps the values to keys.
/// </summary>
private readonly Dictionary<TValue, TKey> inverseMap;
/// <summary>
/// An instance of the dictionary where the values are the keys, and the keys are the values.
/// </summary>
private readonly BidirectionalDictionary<TValue, TKey> inverseInstance;
/// <summary>
/// Initializes a new instance of the dictionary class with serialized data. </summary>
/// </summary>
/// <param name="info"> The serialization info. </param>
/// <param name="context"> The sserialization context. </param>
protected BidirectionalDictionary(SerializationInfo info, StreamingContext context)
{
this.forwardMap = (Dictionary<TKey, TValue>)info.GetValue("UnderlyingDictionary", typeof(Dictionary<TKey, TValue>));
this.inverseMap = new Dictionary<TValue, TKey>(
forwardMap.Count,
(IEqualityComparer<TValue>)info.GetValue("InverseComparer", typeof(IEqualityComparer<TValue>)));
// forwardMap is always empty at this point.
foreach (KeyValuePair<TKey, TValue> entry in forwardMap)
inverseMap.Add(entry.Value, entry.Key);
this.inverseInstance = new BidirectionalDictionary<TValue, TKey>(this);
}
/// <summary>
/// Gets the data needed to serialize the dictionary.
/// </summary>
/// <param name="info"> The serialization info. </param>
/// <param name="context"> The serialization context. </param>
public void GetObjectData(SerializationInfo info, StreamingContext context)
{
info.AddValue("UnderlyingDictionary", forwardMap);
info.AddValue("InverseComparer", inverseMap.Comparer);
}
}
Since the forward- and inverseMap dictionaries contain the exact same data, my idea was to only serialize one of them (forwardMap), and then build the other (inverseMap) from it's data on deserialization. However, the inverseMap isn't getting populated with any data in the deserialization constructor. It seems the forwardMap dictionary is only completely deserialized after the class' deserialization constructor has already executed.
Any idea on how to fix this?
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