c# - Replace a object in a list of objects

Question

In C#, if I have a List<T>, and I have an object of type T, how can I replace a specific item in the List<T> with the object of type T?

Here is what I have tried:

List<CustomListItem> customListItems = new List<CustomListItem>();
CustomListItem customListItem1 = new CustomListItem() { name = "Item 1", date = DateTime.MinValue};
CustomListItem customListItem2 = new CustomListItem() { name = "Item 2", date = DateTime.MinValue };
CustomListItem customListItem3 = new CustomListItem() { name = "Item 3", date = DateTime.MinValue };

customListItems.Add(customListItem1);
customListItems.Add(customListItem2);
customListItems.Add(customListItem3);

CustomListItem newCustomListItem = new CustomListItem() { name = "Item 4", date = DateTime.Now };

customListItem2 = customListItems.Where(i=> i.name == "Item 2").First();
customListItem2 = newCustomListItem;

In the above code, I want to replace the customListItem2 with the newCustomListItem.

Do I have to remove the item in the list, and then insert the new item? Can I not do a simple assignment of customListItem2 = newCustomListItem?

What is the most efficient way of replacing an item in a list with another item?

Thanks in advance

question from:https://stackoverflow.com/questions/26752909/replace-a-object-in-a-list-of-objects

Answer 1

You have to replace the item, not the value of customListItem2. Just replace following:

customListItem2 = customListItems.Where(i=> i.name == "Item 2").First();
customListItem2 = newCustomListItem;

With this:

customListItem2 = customListItems.Where(i=> i.name == "Item 2").First();
var index = customListItems.IndexOf(customListItem2);

if(index != -1)
    customListItems[index] = newCustomListItem;

Edit:

As Roman R. stated in a comment, you can replace the .Where(predicate).First() by a simple First(predicate):

customListItem2 = customListItems.First(i=> i.name == "Item 2");