How would you implement a custom collection in C#?

To implement a custom collection:

• Derive from existing base classes like Collection<T>, List<T>, or implement

interfaces such as ICollection<T>, IEnumerable<T>, or IList<T>.

• Override or implement necessary methods like Add(), Remove(),

GetEnumerator(), and indexers.

• Provide custom behavior, validation, or constraints as needed.

Example:

public class MyCustomCollection<T> : Collection<T>

protected override void InsertItem(int index, T item)

Follow:

// Custom validation

if (item == null) throw new

ArgumentNullException(nameof(item));

base.InsertItem(index, item);