How to remove item from list in C#?

Question

I have a list stored in resultlist as follows:

var resultlist = results.ToList();

It looks something like this:

ID FirstName  LastName
-- ---------  --------
1  Bill       Smith
2  John       Wilson
3  Doug       Berg

How do I remove ID 2 from the list?

Answer 1

List<T> has two methods you can use.

RemoveAt(int index) can be used if you know the index of the item. For example:

resultlist.RemoveAt(1);

Or you can use Remove(T item):

var itemToRemove = resultlist.Single(r => r.Id == 2);
resultList.Remove(itemToRemove);

When you are not sure the item really exists you can use SingleOrDefault. SingleOrDefault will return null if there is no item (Single will throw an exception when it can't find the item). Both will throw when there is a duplicate value (two items with the same id).

var itemToRemove = resultlist.SingleOrDefault(r => r.Id == 2);
if (itemToRemove != null)
    resultList.Remove(itemToRemove);