C# - List<T>.Remove() always deletes the first object on the list

Question

Working in Visual Studio 2008 (C#)... I use a List collection to store instances of my custom class (Shift).

I want to delete a certain shift from the list by using the Remove method.

But List.Remove() always deletes the first item it finds.

I've implemented the IComparable interface for my Shift, I thought this would be enough, then I added an implementation of IEqualityComparer, and it still has no effect.

Here's the excerpt with my implementation:

region IComparable Members

    public int CompareTo(object obj)
    {
        Shift s1 = this;
        Shift s2 = (Shift)obj;
        if (s1.start.time != s2.start.time)
            return s1.start.CompareTo(s2.start);
        else
            return s1.end.CompareTo(s2.end);
    }

endregion

region IEqualityComparer Members

    public bool Equals(Shift x, Shift y)
    {
        
        if ((x.opening) != (y.opening)) return false;
        if ((x.closing) != (y.closing)) return false;
        if (!x.opening) if (x._start != y._start) return false;
        if (!x.closing) if (x._end != y._end) return false;
        if (x.when != y.when) return false;
        if (x.day != y.day) return false;
        if (x.EmployeeID != y.EmployeeID) return false;
        return true;
    }

    public int GetHashCode(Shift obj)
    {
        return obj.ToString().ToLower().GetHashCode();
    }

endregion

And yet, still - when the List contains two shifts, say "8:00 - 15:00"; "12:00 - 16:00", calling Remove("12:00-16:00") results in "8:00 - 15:00" getting removed, and the latter one remains in the collection!

What's wrong here? Thx

Answer 1

You can override object.GetHashCode and object.Equals:

public override bool Equals(object obj)
{
    if(obj == null)
    {
        return false;
    }
    return Equals(this, obj as Shift);
}

public override int GetHashCode()
{
    return this.GetHashCode(this);
}

You should also probably do a null check in Equals(x, y).