C#：是否可以使用表达式或函数作为字典中的键？

发布于 2024-07-27 12:00:17 字数 939 浏览 5 评论 0 原文

使用 Expression> 或 Func 作为字典中的键是否有效？例如缓存大量计算的结果。

例如，从我的不同问题更改我的非常基本的缓存一点：

public static class Cache<T>
{
    // Alternatively using Expression<Func<T>> instead
    private static Dictionary<Func<T>, T> cache;
    static Cache()
    {
        cache = new Dictionary<Func<T>, T>();
    }
    public static T GetResult(Func<T> f)
    {
        if (cache.ContainsKey(f))
            return cache[f];

       return cache[f] = f();
    }
}

这还能用吗？

编辑：经过快速测试，看起来它确实有效。但我发现它可能更通用，因为它现在是每个返回类型一个缓存...不知道如何更改它以免发生这种情况...嗯

编辑2：不，等等...实际上不是。嗯，对于常规方法来说确实如此。但不适用于 lambda。即使它们看起来相同，它们也会获得各种随机方法名称。哦，好吧 c",)

原文

Would it work to use Expression<Func<T>> or Func<T> as keys in a dictionary? For example to cache the result of heavy calculations.

For example, changing my very basic cache from a different question of mine a bit:

public static class Cache<T>
{
    // Alternatively using Expression<Func<T>> instead
    private static Dictionary<Func<T>, T> cache;
    static Cache()
    {
        cache = new Dictionary<Func<T>, T>();
    }
    public static T GetResult(Func<T> f)
    {
        if (cache.ContainsKey(f))
            return cache[f];

       return cache[f] = f();
    }
}

Would this even work?

Edit: After a quick test, it seems like it actually works. But I discovered that it could probably be more generic, since it would now be one cache per return type... not sure how to change it so that wouldn't happen though... hmm

Edit 2: Noo, wait... it actually doesn't. Well, for regular methods it does. But not for lambdas. They get various random method names even if they look the same. Oh well c",)