Dictionary custom comparer to get dictinct of custom object

Question

I want to use my comparer MyComparer to be able to get uniques Vector s from my dictionary. The problem is the result of uniques is wrong. I tried to put breakpoint inside MyComparer but somehow when this line is reached var uniques = map.Distinct(new MyComparer()); it doesn't goes into MyComparer for unknown reason. Why is that? The second point is does the logic inside MyComparer enough to compare Vector s in my dictionary and get the uniques?

Filling up dictionary

var map = new Dictionary<Vector, int>();
for (int i = 0; i < N; i++)
                map.Add(new Vector { A = s[0, i], B = s[0, i + 1], C = s[1, i], D = s[1, i + 1] }, i);

            var uniques = map.Distinct(new MyComparer());

Vector class:

class Vector
{
            public int A { get; set; }
            public int B { get; set; }
            public int C { get; set; }
            public int D { get; set; }
}

MyComparer

class MyComparer : IEqualityComparer<KeyValuePair<Vector, int>>
{
       public bool Equals(KeyValuePair<Vector, int> x, KeyValuePair<Vector, int> y)
       {
             return x.Key == y.Key;
       }

       public int GetHashCode(KeyValuePair<Vector, int> obj)
       {
           return 1;
       }
}

Answer 1

The reason your not seeing it hit the breakpoint is because you're not "resolving" the IEnumerable.

For example when I run this code:

var thing = map.Where(pair => pair.Key == 1);

I get an IEnumerable back, it will only resolve the IEnumerable value (or result) once I use the type. The easiest way to do this is just to add a .ToList();

var uniques = map.Distinct(new MyComparer())
                .ToList();

Now your breakpoints should be hit.