ICollection ICollection ICollection ICollection Interface

Definition

Namespace:
System.Collections System.Collections System.Collections System.Collections
Assemblies:
System.Runtime.dll, mscorlib.dll, netstandard.dll

Defines size, enumerators, and synchronization methods for all nongeneric collections.

public interface class ICollection : System::Collections::IEnumerable
[System.Runtime.InteropServices.ComVisible(true)]
public interface ICollection : System.Collections.IEnumerable
type ICollection = interface
    interface IEnumerable
Public Interface ICollection
Implements IEnumerable
Derived
Attributes
ComVisibleAttribute
Implements
IEnumerableIEnumerableIEnumerableIEnumerable

Remarks

The ICollection interface is the base interface for classes in the System.Collections namespace. Its generic equivalent is the System.Collections.Generic.ICollection<T> interface.

The ICollection interface extends IEnumerable; IDictionary and IList are more specialized interfaces that extend ICollection. An IDictionary implementation is a collection of key/value pairs, like the Hashtable class. An IList implementation is a collection of values and its members can be accessed by index, like the ArrayList class.

Some collections that limit access to their elements, such as the Queue class and the Stack class, directly implement the ICollection interface.

If neither the IDictionary interface nor the IList interface meet the requirements of the required collection, derive the new collection class from the ICollection interface instead for more flexibility.

For the generic version of this interface, see System.Collections.Generic.ICollection<T>.

Properties

Count Count Count Count

Gets the number of elements contained in the ICollection.
IsSynchronized IsSynchronized IsSynchronized IsSynchronized

Gets a value indicating whether access to the ICollection is synchronized (thread safe).
SyncRoot SyncRoot SyncRoot SyncRoot

Gets an object that can be used to synchronize access to the ICollection.

Methods

CopyTo(Array, Int32) CopyTo(Array, Int32) CopyTo(Array, Int32) CopyTo(Array, Int32)

Copies the elements of the ICollection to an Array, starting at a particular Array index.

Extension Methods

Cast<TResult>(IEnumerable) Cast<TResult>(IEnumerable) Cast<TResult>(IEnumerable) Cast<TResult>(IEnumerable)

Casts the elements of an IEnumerable to the specified type.
OfType<TResult>(IEnumerable) OfType<TResult>(IEnumerable) OfType<TResult>(IEnumerable) OfType<TResult>(IEnumerable)

Filters the elements of an IEnumerable based on a specified type.
AsParallel(IEnumerable) AsParallel(IEnumerable) AsParallel(IEnumerable) AsParallel(IEnumerable)

Enables parallelization of a query.
AsQueryable(IEnumerable) AsQueryable(IEnumerable) AsQueryable(IEnumerable) AsQueryable(IEnumerable)

Converts an IEnumerable to an IQueryable.

Applies to

See also