C#中的"详细词典","覆盖新"这个[]或实现IDictionary

Question

我想要的只是一本字典,告诉我它找不到哪个键,而不仅仅是说The given key was not present in the dictionary.

我简单地考虑过做一个子类override new this[TKey key],但觉得它有点hacky,所以我已经实现了IDictionary接口,并将所有内容直接传递给内部Dictionary,并且索引器中只有其他逻辑:

public TValue this[TKey key]
{
    get
    {
        ThrowIfKeyNotFound(key);
        return _dic[key];
    }
    set
    {
        ThrowIfKeyNotFound(key);
        _dic[key] = value;
    }
}
private void ThrowIfKeyNotFound(TKey key)
{
    if(!_dic.ContainsKey(key))
        throw new ArgumentOutOfRangeException("Can't find key [" + key + "] in dictionary");
}

这是正确的/唯一的方法吗？对这个[]的新作真的会那么糟糕吗？

Answer 1

听起来非常适合扩展方法:

public static class SomeUtilClass {
    public static TValue VerboseGetValue<TKey, TValue>(
        this IDictionary<TKey, TValue> data, TKey key)
    {
        TValue result;
        if (!data.TryGetValue(key, out result)) {
            throw new KeyNotFoundException(
                "Key not found: " + Convert.ToString(key));
        }
        return result;
    }
}

然后,只要您打电话VerboseGetValue,这将适用于您现有的所有词典,例如:

    var data = new Dictionary<int, string> { { 123, "abc" } };
    Console.WriteLine(data.VerboseGetValue(123));
    Console.WriteLine(data.VerboseGetValue(456));