How to do Previous and Next item on a List<G>

I have a class called Person, which contains various properties such as first name, last name, etc.

I have a List that contains n instances of Person.

List<Person> lstPerson = new List<Person>();

What I need to be able to do is search lstPerson for a given person, and having found that person then obtain the previous and next person relative to the person's item position in lstPerson.

Person p = lstPerson.Find(delegate(Person o) { return o.FirstName == "Joe"; })开发者_运维技巧;

// Then use an accessor to get the previous and next persons
Person prevPerson = p.Previous();
Person nextPerson = p.Next();

Is there a better way to do this then the one that I stated above? What I don't like about the above solution is that I have to construct the previous and next pointers at the time that I build the Person List.

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You could do something like the following:

int personIndex = lstPerson.FindIndex(delegate(Person o) { return o.FirstName == "Joe" });
Person p = lstPerson[personIndex];
// verify that personIndex+1 and personIndex-1 still fall within the list
Person prevPerson = lstPerson[personIndex-1];
Person nextPerson = lstPerson[personIndex+1];

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Hmm.. why not simply using the LinkedList class? It comes with Next and Previous built in.

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You could do this, which skips elements until the next element matches or it has gone through the entire list:

var list = (new List<Person>() { null }).Concat(lstPerson);
var p = list.SkipWhile((x, index) => { var n = list.ElementAtOrDefault(index + 1); return n == null || n.FirstName != name; }).Take(3);

Person previous = p.FirstOrDefault();
Person person = p.ElementAtOrDefault(1);
Person next = p.ElementAtOrDefault(2);

Although this (similar to @marcind's answer) might be clearer:

Person person = lstPerson.Find(p => p.FirstName == name);
Person previous = null;
Person next = null;

if (person != null)
{
    int index = lstPerson.IndexOf(person);
    previous = lstPerson.ElementAtOrDefault(index - 1);
    next = lstPerson.ElementAtOrDefault(index + 1);
}