How can i get items which are equal to string[] ?

Question

Hi,

I have an array of strings

var controlsToGet = new[] {"lblHome","lblContact"};

I have List<LanguageControl> and LanguageControl class holds Controls in it. I want to get Controls from List which Control.Name == controlsToGet

I am looking for something like that

var all = fooelements.where(l=>l.Control.Name == controlsToGet);

Is it possible with lambda or linq.

Note: I was able to do it with Nhibernate's Disjunction, i am looking for something like that

EDIT : What would i do if i want to use this query for data base with the Entity Framework ?

Thank you

Answer 1

var all = fooelements
              .Where(l=>controlsToGet
                            .Contains(l.Control.Name));

---

If each item has a list of controls:

var all = fooelements
              .SelectMany(l => l.Controls)
              .Where(c => controlsToGet
                             .Contains(c.Name));

Answer 2

var all = from control in listofcontrols
          from toGet  in controlsToGet
          where toGet == control.name
          select control;

Answer 3

If controlsToGet is a string, this will work:

var all = fooelements.SelectMany(l => l.Controls).Where(c => c.Name == controlsToGet);

However, if it's a List<string> you will need:

var all = fooelements.SelectMany(l => l.Controls).Where(c => controlsToGet.Contains(c.Name));

Answer 4

You could also use the findall. If microsoft optimise the method you will increase performance, if not it's will be the same as the foreach

var result = fooelements.FindAll(item=> controlsToGet.Contains(item.Name));

Answer 5

A naïve solution such as:

fooelements.SelectMany(l => l.Controls).Where(c => controlsToGet.Contains(c.Name))

is O(n*m) where n is the number of controls, and m is the number of strings in your name array. Some may argue that this is nitpicking and YAGNI and ... (yadda yadda), but what the heck - just a little more code gives you an O(n) solution:

var controlsToGet = new HashSet<string> { "lblHome", "lblContact" };
var controls = fooelements.SelectMany(l => l.Controls)
    .Where(c => controlsToGet.Contains(c.Name))