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ObservableCollection<T> Class

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Represents a dynamic data collection that provides notifications when items get added, removed, or when the entire list is refreshed.

Namespace:  System.Collections.ObjectModel
Assembly:  System.Windows (in System.Windows.dll)

Syntax

'Declaration
Public Class ObservableCollection(Of T) _
    Inherits Collection(Of T) _
    Implements INotifyCollectionChanged, INotifyPropertyChanged

public class ObservableCollection<T> : Collection<T>, 
    INotifyCollectionChanged, INotifyPropertyChanged

Type Parameters

  • T
    The type of items in the collection.

The ObservableCollection<T> type exposes the following members.

Constructors

  Name Description
Public methodSupported by Silverlight for Windows Phone ObservableCollection<T>() Initializes a new, empty instance of the ObservableCollection<T> class.
Public methodSupported by Silverlight for Windows Phone ObservableCollection<T>(IEnumerable<T>) Initializes a new instance of the ObservableCollection<T> class and populates it with items copied from the specified collection.
Public methodSupported by Silverlight for Windows Phone ObservableCollection<T>(List<T>) Initializes a new instance of the ObservableCollection<T> class and populates it with items copied from the specified list.

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Properties

  Name Description
Public propertySupported by Silverlight for Windows Phone Count Gets the number of elements actually contained in the Collection<T>. (Inherited from Collection<T>.)
Public propertySupported by Silverlight for Windows Phone Item Gets or sets the element at the specified index. (Inherited from Collection<T>.)
Protected propertySupported by Silverlight for Windows Phone Items Gets a IList<T> wrapper around the Collection<T>. (Inherited from Collection<T>.)

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Methods

  Name Description
Public methodSupported by Silverlight for Windows Phone Add Adds an object to the end of the Collection<T>. (Inherited from Collection<T>.)
Public methodSupported by Silverlight for Windows Phone Clear Removes all elements from the Collection<T>. (Inherited from Collection<T>.)
Protected methodSupported by Silverlight for Windows Phone ClearItems Removes all items from the collection. (Overrides Collection<T>.ClearItems().)
Public methodSupported by Silverlight for Windows Phone Contains Determines whether an element is in the Collection<T>. (Inherited from Collection<T>.)
Public methodSupported by Silverlight for Windows Phone CopyTo Copies the entire Collection<T> to a compatible one-dimensional Array, starting at the specified index of the target array. (Inherited from Collection<T>.)
Public methodSupported by Silverlight for Windows Phone Equals(Object) Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
Protected methodSupported by Silverlight for Windows Phone Finalize Allows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.)
Public methodSupported by Silverlight for Windows Phone GetEnumerator Returns an enumerator that iterates through the Collection<T>. (Inherited from Collection<T>.)
Public methodSupported by Silverlight for Windows Phone GetHashCode Serves as a hash function for a particular type. (Inherited from Object.)
Public methodSupported by Silverlight for Windows Phone GetType Gets the Type of the current instance. (Inherited from Object.)
Public methodSupported by Silverlight for Windows Phone IndexOf Searches for the specified object and returns the zero-based index of the first occurrence within the entire Collection<T>. (Inherited from Collection<T>.)
Public methodSupported by Silverlight for Windows Phone Insert Inserts an element into the Collection<T> at the specified index. (Inherited from Collection<T>.)
Protected methodSupported by Silverlight for Windows Phone InsertItem Inserts an item into the collection at the specified index. (Overrides Collection<T>.InsertItem(Int32, T).)
Protected methodSupported by Silverlight for Windows Phone MemberwiseClone Creates a shallow copy of the current Object. (Inherited from Object.)
Protected methodSupported by Silverlight for Windows Phone OnCollectionChanged Raises the CollectionChanged event with the provided event data.
Protected methodSupported by Silverlight for Windows Phone OnPropertyChanged Raises the PropertyChanged event with the provided arguments.
Public methodSupported by Silverlight for Windows Phone Remove Removes the first occurrence of a specific object from the Collection<T>. (Inherited from Collection<T>.)
Public methodSupported by Silverlight for Windows Phone RemoveAt Removes the element at the specified index of the Collection<T>. (Inherited from Collection<T>.)
Protected methodSupported by Silverlight for Windows Phone RemoveItem Removes the item at the specified index from the collection. (Overrides Collection<T>.RemoveItem(Int32).)
Protected methodSupported by Silverlight for Windows Phone SetItem Replaces the item at the specified index. (Overrides Collection<T>.SetItem(Int32, T).)
Public methodSupported by Silverlight for Windows Phone ToString Returns a string that represents the current object. (Inherited from Object.)

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Events

  Name Description
Public eventSupported by Silverlight for Windows Phone CollectionChanged Occurs when an item in the collection changes, or the entire collection changes.
Protected eventSupported by Silverlight for Windows Phone PropertyChanged Occurs when a property on an individual item in the collection changes.

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Explicit Interface Implementations

  Name Description
Explicit interface implemetationPrivate methodSupported by Silverlight for Windows Phone ICollection.CopyTo Copies the elements of the ICollection to an Array, starting at a particular Array index. (Inherited from Collection<T>.)
Explicit interface implemetationPrivate propertySupported by Silverlight for Windows Phone ICollection<T>.IsReadOnly Gets a value indicating whether the ICollection<T> is read-only. (Inherited from Collection<T>.)
Explicit interface implemetationPrivate propertySupported by Silverlight for Windows Phone ICollection.IsSynchronized Gets a value indicating whether access to the ICollection is synchronized (thread safe). (Inherited from Collection<T>.)
Explicit interface implemetationPrivate propertySupported by Silverlight for Windows Phone ICollection.SyncRoot Gets an object that can be used to synchronize access to the ICollection. (Inherited from Collection<T>.)
Explicit interface implemetationPrivate methodSupported by Silverlight for Windows Phone IEnumerable.GetEnumerator Returns an enumerator that iterates through a collection. (Inherited from Collection<T>.)
Explicit interface implemetationPrivate methodSupported by Silverlight for Windows Phone IList.Add Adds an item to the IList. (Inherited from Collection<T>.)
Explicit interface implemetationPrivate methodSupported by Silverlight for Windows Phone IList.Contains Determines whether the IList contains a specific value. (Inherited from Collection<T>.)
Explicit interface implemetationPrivate methodSupported by Silverlight for Windows Phone IList.IndexOf Determines the index of a specific item in the IList. (Inherited from Collection<T>.)
Explicit interface implemetationPrivate methodSupported by Silverlight for Windows Phone IList.Insert Inserts an item into the IList at the specified index. (Inherited from Collection<T>.)
Explicit interface implemetationPrivate propertySupported by Silverlight for Windows Phone IList.IsFixedSize Gets a value indicating whether the IList has a fixed size. (Inherited from Collection<T>.)
Explicit interface implemetationPrivate propertySupported by Silverlight for Windows Phone IList.IsReadOnly Gets a value indicating whether the IList is read-only. (Inherited from Collection<T>.)
Explicit interface implemetationPrivate propertySupported by Silverlight for Windows Phone IList.Item Gets or sets the element at the specified index. (Inherited from Collection<T>.)
Explicit interface implemetationPrivate methodSupported by Silverlight for Windows Phone IList.Remove Removes the first occurrence of a specific object from the IList. (Inherited from Collection<T>.)
Explicit interface implemetationPrivate event INotifyPropertyChanged.PropertyChanged Infrastructure. Occurs when a property value changes.

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Remarks

You can enumerate over any collection that implements the IEnumerable interface, and this is sufficient for one-time data binding in Silverlight. However, to set up dynamic bindings so that insertions or deletions in the collection can update the UI automatically, the collection must implement the INotifyCollectionChanged interface. This interface exposes the CollectionChanged event, an event that should be raised whenever the underlying collection changes.

Silverlight provides the ObservableCollection<T> class, which is a base class data collection that implements the INotifyCollectionChanged interface, as well as the INotifyPropertyChanged interface. It also has the expected collection support, defined by deriving from the Collection<T> class.

For an example, see How to: Bind to Hierarchical Data and Create a Master/Details View.

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.