Find next record in a set: LINQ

Question

I have a list of objects which all have an id property

E.g

1, 10, 25, 30, 4

I have a currentId and I need to find the next Id in the list

So

Answer 1

There are quite a few solution. I suggest something like the following.

var next = items
    .Where(item => item.Id > currentId)
    .OrderBy(item => item.Id)
    .First();

var next = items
    .OrderBy(item => item.Id)
    .First(item => item.Id > currentId);

If you want the ids in the order they appear in the collection, you could use the following.

var next = items
    .SkipWhile(item => item.Id != currentId)
    .Skip(1)
    .FirstOrDefault();

If this returns null, you have tried to get next item of the last item.

Answer 2

Without re-ordering (note I edit slightly as I think I misread the question):

int[] data = {1, 10, 25, 30, 4};
int last = 25;
var next = data.SkipWhile(i => i != last).Skip(1).First();

Obviously, if data was a set of objects, something like:

var next = data.SkipWhile(obj => obj.Id != last).Skip(1).First();

Answer 3

int currentId = 25;
var next = yourCollection.Where(i => i.Id > currentId).OrderBy(i => i.Id).First();