Elegant way to query a dictionary in C#

Question

I am trying to create an elegant and extensible way of querying a dictionary which maps an enum to a set of strings.

So I have this class SearchFragments that has the dictionary in it. I then want a method wherein consumers of this class can simply ask "HasAny" and, this is the bit where I am struggling, simply pass in some query like expression and get the boolean answer back.

public class SearchFragments
{
    private readonly IDictionary<SearchFragmentEnum, IEnumerable<string>> _fragments;

    public SearchFragments()
    {
        _fragments = new Dictionary<SearchFragmentEnum, IEnumerable<string>>();
    }

    public bool HasAny(IEnumerable<SearchFragmentEnum> of)
    {
        int has = 0;
        _fragments.ForEach(x => of.ForEach(y => has += x.Key == y ? 1 : 0));
        return has >= 1;
    }
}

The problem with the way this currently is, is that consumers of this class now have to construct an IEnumerable<SearchFragmentEnum> which can be quite messy.

What I am looking for is that the consuming code will be able to write something along the lines of:

searchFragments.HasAny(SearchFragmentEnum.Name, SearchFragmentEnum.PhoneNumber)

But where that argument list can vary in size (without me having to write method overloads in the SearchFragments class for every possible combination (such that if new values are added to the SearchFragmentEnum at a future date I won't have to update the class.

Answer 1

You can use params[]

public bool HasAny(params SearchFragmentEnum[] of)
{ ...

Sidenote: you know that LIN(Q) queries should just query a source and never cause any side-effects? But your query does unnecessarily increment the integer:

_fragments.ForEach(x => of.ForEach(y => has += x.Key == y ? 1 : 0));

Instead use this (which is also more efficient and more readable):

return _fragments.Keys.Intersect(of).Any();

---

An even more efficient alternative to this is Sergey's idea:

return of?.Any(_fragments.ContainsKey) == true;