C# – ICollection

ICollection<T> and ICollection

ICollection<T> is the standard interface for countable collections of objects.

It provides the ability to determine the size of a collection (Count).

If the collection is writable you can also Add, Remove and Clear items from the collection.

Collection can be traversed via foreach statement since it extends IEnumerable.

Methods and Properties

Contains – determine whether an item exists in the collection.

ToArray – copy the collection into an array.

IsReadOnly – determine whether the collection is read-only.

Count-size of the collection.

Add– add item to the collection.

Remove– remove item from collection.

Clear– clear collection.

Generic Collection

public interface ICollection<T> : IEnumerable<T>, IEnumerable
{
	int Count { get; }
	
	bool Contains (T item);
	void CopyTo (T[] array, int arrayIndex);
	bool IsReadOnly { get; }

	void Add(T item);
	bool Remove (T item);
	void Clear();
}

Non Generic Collection

public interface ICollection : IEnumerable
{
	int Count { get; }
	bool IsSynchronized { get; }
	object SyncRoot { get; }
	void CopyTo (Array array, int index);
}

The interface is implemented in conjunction with either IList or IDictionary.