编译时间通用类型约束不相同

Question

我想创建一个实现BiDiDictionary<T1, T2>和IDictionary<T1, T2>的双向查找IDictionary<T2, T1>：

class BiDiDictionary<T1, T2> : IDictionary<T1, T2>, IDictionary<T2, T1>
{
    IDictionary<T1, T2> _t1t2 = new Dictionary<T1, T2>();
    IDictionary<T2, T1> _t2t1 = new Dictionary<T2, T1>();
    public void Add(T1 key, T2 value)
    {
        _t1t2.Add(key, value);
        _t2t1.Add(value, key);
    }

    public bool ContainsKey(T1 key)
    {
        return _t1t2.ContainsKey(key);
    }

    public ICollection<T1> Keys
    {
        get { return _t1t2.Keys; }
    }

    public bool Remove(T1 key)
    {
        var t2 = _t1t2[key];
        _t1t2.Remove(key);
        _t2t1.Remove(t2);
    }

    public bool TryGetValue(T1 key, out T2 value)
    {
        return _t1t2.TryGetValue(key, out value);
    }

    public ICollection<T2> Values
    {
        get { return _t1t2.Values; }
    }

    public T2 this[T1 key]
    {
        get
        {
            return _t1t2[key];
        }
        set
        {
            _t1t2[key] = value;
            _t2t1[value] = key;
        }
    }

    public void Add(KeyValuePair<T1, T2> item)
    {
        Add(item.Key, item.Value);
    }

    public void Clear()
    {
        _t1t2.Clear();
        _t2t1.Clear();
    }

    public bool Contains(KeyValuePair<T1, T2> item)
    {
        return _t1t2.Contains(item);
    }

    public void CopyTo(KeyValuePair<T1, T2>[] array, int arrayIndex)
    {
        _t1t2.CopyTo(array, arrayIndex);
    }

    public int Count
    {
        get { return _t1t2.Count; }
    }

    public bool IsReadOnly
    {
        get { return false; }
    }

    public bool Remove(KeyValuePair<T1, T2> item)
    {
        Remove(item.Key);
    }

    public IEnumerator<KeyValuePair<T1, T2>> GetEnumerator()
    {
        return _t1t2.GetEnumerator();
    }

    System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
    {
        return GetEnumerator();
    }

    public void Add(T2 key, T1 value)
    {
        Add(value, key);
    }

    public bool ContainsKey(T2 key)
    {
        return _t2t1.ContainsKey(key);
    }

    ICollection<T2> IDictionary<T2, T1>.Keys
    {
        get { return _t2t1.Keys; }
    }

    public bool Remove(T2 key)
    {
        var t1 = _t2t1[key];
        _t1t2.Remove(t1);
        _t2t1.Remove(key);
    }

    public bool TryGetValue(T2 key, out T1 value)
    {
        return _t2t1.TryGetValue(key, out value);
    }

    ICollection<T1> IDictionary<T2, T1>.Values
    {
        get { return _t2t1.Values; }
    }

    public T1 this[T2 key]
    {
        get
        {
            return _t2t1[key];
        }
        set
        {
            this[value] = key;
        }
    }

    public void Add(KeyValuePair<T2, T1> item)
    {
        Add(item.Key, item.Value);
    }

    public bool Contains(KeyValuePair<T2, T1> item)
    {
        return _t2t1.Contains(item);
    }

    public void CopyTo(KeyValuePair<T2, T1>[] array, int arrayIndex)
    {
        _t2t1.CopyTo(array, arrayIndex);
    }

    public bool Remove(KeyValuePair<T2, T1> item)
    {
        return Remove(item.Key);
    }

    IEnumerator<KeyValuePair<T2, T1>> IEnumerable<KeyValuePair<T2, T1>>.GetEnumerator()
    {
        return _t2t1.GetEnumerator();
    }
}

但是，尝试编译它会导致以下错误：

  

BiDiDictionary<T1,T2>无法实现Dictionary<T1,T2>和Dictionary<T2,T1>，因为它们可能会针对某些类型参数替换进行统一

有没有办法向编译器表明我已经意识到这个问题，并且只有在有人试图使用T1和T2的类时才会引发错误？< / p>