获取具有当前ID的对象之后列表中的下一个对象

Question

I know the title is confusing so I will try my best to explain here...

I have

class T{
   int id;
   string value;
}


List<T> objs;

in my code when I retrieve the initial list I grab the first id with

int currentID = objs.FirstOrDefault().id;

now I need to grab next. not knowing the current position of where I am how can I grab the next item id...

 objs.select(x => x.id)
        .where(//you are the object that exists after the one with currentID);

Answer 1

如果要在某个元素之后获取下一个元素，则可以使用SkipWhile()和Skip()方法：

objs.SkipWhile(x => x.id == currentID).Skip(1).FirstOrDefault();

Answer 2

You are just indexing, so use ElementAt :

int i = 0; //current position
int currentID = objs.ElementAt(i).id;
i++;

Execute in a loop to get the next one, etc.

If you actually just want to iterate through all elements, just use a foreach :

foreach (T obj in objs)
{
   int currentID = obj.id;
}

Finally, you could use GetEnumerator and utilize the MoveNext function along with the Current property. This is basically using a foreach but controlling the iteration yourself.