Question

I used to ask a similar question which was aiming to understand how to get the models at the other set which are having the same property with the one I am holding.

Now the problem is:
So, what was the name of the “similar property” which actually guided me to the other set.

The original post was:
C# LINQ to Entities query for the intersection of two different properties

I have 3 models named:

1. Pencil having Pencil.Id(int) and Pencil.Colors(IEnumerable) Property
2. Pen having Pen.Id(int) and Pen.Colors(IEnumerable) Property
3. Colors having Id and name.

Colors model is IEnumerable so it has more than 1 color. For example; the pen has 15 different colors and pencil is having 25 different colors. I want to bring the corresonding pencil if one of the colors of the pen that I am holding is also avaialable in the color palette of that pencil.

Raphael‘s great solution is https://stackoverflow.com/a/11722191/1062284

int id = id_of_the_pen_that_i_am_holding;
Pen p = db.Pens.Find(id);
var penColorIds = p.Color.Select(m => m.Id).ToList();
var list = db.Pencils.Where(pencil => pencil.Color.Any(color => penColorIds.Contains(color.Id));

So it is OK and working like a charm but how about learning the name of the common colors?
We get the other properties which are holding the same color but what was that color?

I will appreciate if some one can produce this LINQ query. I am pretty new for LINQ and will much appreciate any help.

Answer 1

If you are holding multiple pens in your hand then use (in variable pens)

var colors = pens.SelectMany(p=>p.Colors).Distinct(); 
var commonColors = db.Pencils.SelectMany (p => p.Colors.Where(c=>colors.Contains(c))).Distinct()

Else if you only have one pen (in variable pen)

var colors = pen.Colors;
var commonColors = db.Pencils.SelectMany (p => p.Colors.Where(c=>colors.Contains(c))).Distinct()