ObservableCollection(Of T) Class

May 11, 2014

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 (in System.dll)

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

Type Parameters

T

The type of items in the collection.

The ObservableCollection(Of T) type exposes the following members.

  NameDescription
Public methodObservableCollection(Of T)Initializes a new, empty instance of the ObservableCollection(Of T) class.
Public methodObservableCollection(Of T)(IEnumerable(Of T))Initializes a new instance of the ObservableCollection(Of T) class and populates it with items copied from the specified collection.
Public methodObservableCollection(Of T)(List(Of T))Initializes a new instance of the ObservableCollection(Of T) class and populates it with items copied from the specified list.
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  NameDescription
Public propertyCountGets the number of elements actually contained in the Collection(Of T). (Inherited from Collection(Of T).)
Public propertyItemGets or sets the element at the specified index. (Inherited from Collection(Of T).)
Protected propertyItemsGets a IList(Of T) wrapper around the Collection(Of T). (Inherited from Collection(Of T).)
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  NameDescription
Public methodAddAdds an object to the end of the Collection(Of T). (Inherited from Collection(Of T).)
Protected methodBlockReentrancyDisallows reentrant attempts to change this collection.
Protected methodCheckReentrancyChecks for reentrant attempts to change this collection.
Public methodClearRemoves all elements from the Collection(Of T). (Inherited from Collection(Of T).)
Protected methodClearItemsRemoves all items from the collection. (Overrides Collection(Of T).ClearItems.)
Public methodContainsDetermines whether an element is in the Collection(Of T). (Inherited from Collection(Of T).)
Public methodCopyToCopies the entire Collection(Of T) to a compatible one-dimensional Array, starting at the specified index of the target array. (Inherited from Collection(Of T).)
Public methodEquals(Object)Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.)
Public methodGetEnumeratorReturns an enumerator that iterates through the Collection(Of T). (Inherited from Collection(Of T).)
Public methodGetHashCodeServes as a hash function for a particular type. (Inherited from Object.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodIndexOfSearches for the specified object and returns the zero-based index of the first occurrence within the entire Collection(Of T). (Inherited from Collection(Of T).)
Public methodInsertInserts an element into the Collection(Of T) at the specified index. (Inherited from Collection(Of T).)
Protected methodInsertItemInserts an item into the collection at the specified index. (Overrides Collection(Of T).InsertItem(Int32, T).)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodMoveMoves the item at the specified index to a new location in the collection.
Protected methodMoveItemMoves the item at the specified index to a new location in the collection.
Protected methodOnCollectionChangedRaises the CollectionChanged event with the provided event data.
Protected methodOnPropertyChangedRaises the PropertyChanged event with the provided arguments.
Public methodRemoveRemoves the first occurrence of a specific object from the Collection(Of T). (Inherited from Collection(Of T).)
Public methodRemoveAtRemoves the element at the specified index of the Collection(Of T). (Inherited from Collection(Of T).)
Protected methodRemoveItemRemoves the item at the specified index from the collection. (Overrides Collection(Of T).RemoveItem(Int32).)
Protected methodSetItemReplaces the item at the specified index. (Overrides Collection(Of T).SetItem(Int32, T).)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)
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  NameDescription
Public eventCollectionChangedOccurs when an item in the collection changes, or the entire collection changes.
Protected eventPropertyChangedOccurs when a property on an individual item in the collection changes.
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  NameDescription
Explicit interface implemetationPrivate methodICollection.CopyToCopies the elements of the ICollection to an Array, starting at a particular Array index. (Inherited from Collection(Of T).)
Explicit interface implemetationPrivate propertyICollection(Of T).IsReadOnlyGets a value indicating whether the ICollection(Of T) is read-only. (Inherited from Collection(Of T).)
Explicit interface implemetationPrivate propertyICollection.IsSynchronizedGets a value indicating whether access to the ICollection is synchronized (thread safe). (Inherited from Collection(Of T).)
Explicit interface implemetationPrivate propertyICollection.SyncRootGets an object that can be used to synchronize access to the ICollection. (Inherited from Collection(Of T).)
Explicit interface implemetationPrivate methodIEnumerable.GetEnumeratorReturns an enumerator that iterates through a collection. (Inherited from Collection(Of T).)
Explicit interface implemetationPrivate methodIList.AddAdds an item to the IList. (Inherited from Collection(Of T).)
Explicit interface implemetationPrivate methodIList.ContainsDetermines whether the IList contains a specific value. (Inherited from Collection(Of T).)
Explicit interface implemetationPrivate methodIList.IndexOfDetermines the index of a specific item in the IList. (Inherited from Collection(Of T).)
Explicit interface implemetationPrivate methodIList.InsertInserts an item into the IList at the specified index. (Inherited from Collection(Of T).)
Explicit interface implemetationPrivate propertyIList.IsFixedSizeGets a value indicating whether the IList has a fixed size. (Inherited from Collection(Of T).)
Explicit interface implemetationPrivate propertyIList.IsReadOnlyGets a value indicating whether the IList is read-only. (Inherited from Collection(Of T).)
Explicit interface implemetationPrivate propertyIList.ItemGets or sets the element at the specified index. (Inherited from Collection(Of T).)
Explicit interface implemetationPrivate methodIList.RemoveRemoves the first occurrence of a specific object from the IList. (Inherited from Collection(Of T).)
Explicit interface implemetationPrivate eventINotifyPropertyChanged.PropertyChangedOccurs when a property value changes.
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You can enumerate over any collection that implements the IEnumerable interface, and this is sufficient for one-time data binding in XAML. 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.

XAML provides the ObservableCollection(Of 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(Of T) class.

Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Windows Phone

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

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