Generic Dictionary value is an Generic Dictionary

Question

I'd like to create a class which contains a generic dictionary which value is an generic dictionary as below:

class DList<T>
{
    public Dictionary<string, Dictionary<K, T>> Dic;
    public Init<K,T>()
    {
        Dic = new Dictionary<string, Dictionary<K, T>>();
        Dic.Add("Name", new Dictionary<string, T>());
        Dic.Add("Id", new Dictionary<int, T>());
    }
}

How can I implement this? Thanks a lot

Answer 1

dynamic works. What I need is almost like a multi-keys Dictionary.

public class DList<T> : IEnumerable
{
    private List<T> list;
    private Dictionary<string, dynamic> dic;

    public T this[int i] => list[i];

    public dynamic this[string j] => dic[j];

    public int Count => list.Count;

    public DList(params string[] properties)
    {
        this.list = new List<T>();
        this.dic = new Dictionary<string, dynamic>();
        foreach (var item in properties)
        {
            this.dic.Add(item, new Dictionary<dynamic, T>());
        }
    }

    public void Add(T t)
    {
        list.Add(t);
        foreach (var item in dic)
        {
            dynamic d = t.GetType()
                .GetField(item.Key)
                .GetValue(t);
            if (item.Value.ContainsKey(d))
                continue;
            item.Value.Add(d, t);
        }
    }

    public T Get(string key, dynamic s)
    {
        return dic[key][s];
    }

    public T Get(int index)
    {
        return list[index];
    }

    public void Clear()
    {
        this.list.Clear();
        foreach(var item in dic)
        {
            item.Value.Clear();
        }
    }

    public void Sort(Comparison<T> Compare)
    {
        list.Sort(Compare);
    }

    public IEnumerator GetEnumerator()
    {
        return list.GetEnumerator();
    }
}

Answer 2

class DList<K, T>
{
    public Dictionary<string, Dictionary<K, T>> Dic;
    public DList()
    {
        Dic = new Dictionary<string, Dictionary<K, T>>();
        Dic.Add("Name", new Dictionary<K, T>());
        Dic.Add("Id", new Dictionary<K, T>());
    }
}


class DList2<K, T>
{
    public Dictionary<string, Dictionary<object, T>> Dic;
    public DList2()
    {
        Dic = new Dictionary<string, Dictionary<object, T>>();
        Dic.Add("Name", new Dictionary<object, T>());
        Dic.Add("Id", new Dictionary<object, T>());
    }
}

If you know K upfront, use the DList approach. If you want to use string , int etc for K , use the approach in DList2 . The inner dictionary will work just fine with keys of type int , string , etc, even if its key is declared as object .