How to group by custom types with linq

Question

I have this class

public class Item
{
       public Coordinate coordinate { get; set; }
        ...
        ...
}

With Coordinate being def

Answer 1

You've shown the Equals implementation, but not GetHashCode. You need to override both (and in a consistent way) for grouping to work.

Sample GetHashCode implementation:

public override int GetHashCode()
{
    int hash = 23;
    hash = hash * 31 + Latitude.GetHashCode();
    hash = hash * 31 + Longitude.GetHashCode();
    return hash;
}

Note that comparing float values for exact equality is always somewhat risky - but I'd at least expect your unit tests to pass, given that they're not performing any calculations.