相关疑难解决方法(0)

我有一个带有属性Id的Foo类.我的目标是同时没有两个具有相同Id的Foo实例.

所以我创建了一个工厂方法CreateFoo,它使用缓存来为同一个Id返回相同的实例.

static Foo CreateFoo(int id) {
    Foo foo;
    if (!cache.TryGetValue(id, out foo)) {
        foo = new Foo(id);
        foo.Initialize(...);
        cache.Put(id, foo);
    }
    return foo;
}

缓存实现为Dictionary <TKey,WeakReference>,基于@JaredPar的Building a WeakReference Hashtable:

class WeakDictionary<TKey, TValue> where TValue : class {
    private readonly Dictionary<TKey, WeakReference> items;
    public WeakDictionary() {
        this.items = new Dictionary<TKey, WeakReference>();
    }
    public void Put(TKey key, TValue value) {
        this.items[key] = new WeakReference(value);
    }
    public …