C#Dictionary不能添加重复键的解决方法

 public class RepeatDictionaryComparer : IEqualityComparer<string>
    {
        public bool Equals(string x, string y)
        {
            return x != y;
        }
        public int GetHashCode(string obj)
        {
            return obj.GetHashCode();
        }
    }

Dictionary<string, string> _dic = new Dictionary<string, string>(new RepeatDictionaryComparer());