Generic dictionary with weakreference value

Hi,

I am trying to bring generic weak reference dictionary in c# 3.0. I have created a class called WeakDictionary which implements IDictionary. This class has a private member as,
private Dictionary weakDictionary = new Dictionary();
The other methods like Add,Remove, Clear are working fine for the weakDictionary. But I could not work out the TryGetValue method. It shows the error InvalidCastException was unhandled - Unable to cast object of type 'System.WeakReference' to type 'System.String'. on the line

value = (TValue)weakReference.Target;

I don't know how to retrieve the value. Please help me.

CODE

public bool TryGetValue(TKey key, out TValue value) {
    WeakReference weakReference;
    if (this.weakDictionary.TryGetValue(key, out weakReference) && weakReference.IsAlive) {
        value = (TValue)weakReference.Target;
        return true;
    } else {
        weakDictionary.Remove(key);
        value = default(TValue);
        return false;
    }
}

Thank you.

2 Replies

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SeethaLakshmi Raja18y ago
As i created weak dictionary as a class library, i tested it with a console application which uses this generic weak dictionary using int for TKey and string for TValue. However, thank you very much. I created a WeakReference class separately to handle the typecast. It worked :)
Alan18y ago
As this is a runtime error, are you sure that your weak reference actually represents a string object?