The System.Collections namespace contains interfaces and classes that define various collections of objects, such as lists, queues, bit arrays, hashtables and dictionaries.
Namespace hierarchy
Classes
| Class | Description |
| ArrayList | Implements the IList interface using an array whose size is dynamically increased as required. |
| BitArray | Manages a compact array of bit values, which are represented as Booleans, where true indicates that the bit is on (1) and false indicates the bit is off (0). |
| CaseInsensitiveComparer | Compares two objects for equivalence, ignoring the case of strings. |
| CaseInsensitiveHashCodeProvider | Supplies a hash code for an object, using a hashing algorithm that ignores the case of strings. |
| CollectionBase | Provides the abstract (MustInherit in Visual Basic) base class for a strongly typed collection. |
| Comparer | Compares two objects for equivalence, where string comparisons are case-sensitive. |
| DictionaryBase | Provides the abstract (MustInherit in Visual Basic) base class for a strongly typed collection of key-and-value pairs. |
| Hashtable | Represents a collection of key-and-value pairs that are organized based on the hash code of the key. |
| Queue | Represents a first-in, first-out collection of objects. |
| ReadOnlyCollectionBase | Provides the abstract (MustInherit in Visual Basic) base class for a strongly typed read-only collection. |
| SortedList | Represents a collection of key-and-value pairs that are sorted by the keys and are accessible by key and by index. |
| Stack | Represents a simple last-in-first-out collection of objects. |
Interfaces
| Interface | Description |
| ICollection | Defines size, enumerators and synchronization methods for all collections. |
| IComparer | Exposes a method that compares two objects. |
| IDictionary | Represents a collection of key-and-value pairs. |
| IDictionaryEnumerator | Enumerates the elements of a dictionary. |
| IEnumerable | Exposes the enumerator, which supports a simple iteration over a collection. |
| IEnumerator | Supports a simple iteration over a collection. |
| IHashCodeProvider | Supplies a hash code for an object, using a custom hash function. |
| IList | Represents a collection of objects that can be individually accessed by index. |
Structures
| Structure | Description |
| DictionaryEntry | Defines a dictionary key-and-value pair that can be set or retrieved. |
See Also
.NET Framework Class Library
