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ItemCollection Class

.NET Framework 4

Holds the list of items that constitute the content of an ItemsControl.

System.Object
  System.Windows.Threading.DispatcherObject
    System.Windows.Data.CollectionView
      System.Windows.Controls.ItemCollection

Namespace:  System.Windows.Controls
Assembly:  PresentationFramework (in PresentationFramework.dll)
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[LocalizabilityAttribute(LocalizationCategory.Ignore)]
public sealed class ItemCollection : CollectionView, 
	IList, ICollection, IEnumerable, IEditableCollectionViewAddNewItem, IEditableCollectionView, 
	IItemProperties, IWeakEventListener

The ItemCollection type exposes the following members.

  Name Description
Public property CanFilter Gets a value that indicates whether this collection view supports filtering. (Overrides CollectionView.CanFilter.)
Public property CanGroup Gets a value that indicates whether this collection view supports grouping. (Overrides CollectionView.CanGroup.)
Public property CanSort Gets a value that indicates whether this collection view supports sorting. (Overrides CollectionView.CanSort.)
Public property Comparer Returns an object that you can use to compare items in the view. (Inherited from CollectionView.)
Public property Count Gets the number of records in the collection. (Overrides CollectionView.Count.)
Public property Culture Gets or sets the culture information to use during sorting. (Inherited from CollectionView.)
Public property CurrentItem Gets the current item in the view. (Overrides CollectionView.CurrentItem.)
Public property CurrentPosition Gets the ordinal position of the current item within the view. (Overrides CollectionView.CurrentPosition.)
Public property Dispatcher Gets the Dispatcher this DispatcherObject is associated with. (Inherited from DispatcherObject.)
Public property Filter Gets or sets a callback used to determine if an item is suitable for inclusion in the view. (Overrides CollectionView.Filter.)
Public property GroupDescriptions Gets a collection of GroupDescription objects that defines how to group the items. (Overrides CollectionView.GroupDescriptions.)
Public property Groups Gets the top-level groups that are constructed according to the GroupDescriptions. (Overrides CollectionView.Groups.)
Public property IsCurrentAfterLast Gets a value that indicates whether the current item of the view is beyond the end of the collection. (Overrides CollectionView.IsCurrentAfterLast.)
Public property IsCurrentBeforeFirst Gets a value that indicates whether the current item of the view is beyond the beginning of the collection. (Overrides CollectionView.IsCurrentBeforeFirst.)
Protected property IsCurrentInSync Gets a value that indicates whether the CurrentItem is at the CurrentPosition. (Inherited from CollectionView.)
Protected property IsDynamic Gets a value that indicates whether the underlying collection provides change notifications. (Inherited from CollectionView.)
Public property IsEmpty Gets a value that indicates whether the resulting (filtered) view is empty. (Overrides CollectionView.IsEmpty.)
Protected property IsRefreshDeferred Gets a value that indicates whether there is an outstanding DeferRefresh in use. (Inherited from CollectionView.)
Public property Item Gets or sets the item at the given zero-based index.
Public property NeedsRefresh Gets a value that indicates whether the collection needs to be refreshed. (Overrides CollectionView.NeedsRefresh.)
Public property SortDescriptions Gets a collection of SortDescription objects that describe how the items in the collection are sorted in the view. (Overrides CollectionView.SortDescriptions.)
Public property SourceCollection Gets the unsorted and unfiltered collection that underlies this collection view. (Overrides CollectionView.SourceCollection.)
Protected property UpdatedOutsideDispatcher Gets a value that indicates whether it has been necessary to update the change log because a CollectionChanged notification has been received on a different thread without first entering the user interface (UI) thread dispatcher. (Inherited from CollectionView.)
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  Name Description
Public method Add Adds an item to the ItemCollection.
Public method CheckAccess Determines whether the calling thread has access to this DispatcherObject. (Inherited from DispatcherObject.)
Public method Clear Clears the collection and releases the references on all items currently in the collection.
Protected method ClearChangeLog Clears any pending changes from the change log. (Inherited from CollectionView.)
Public method Contains Returns a value that indicates whether the specified item is in this view. (Overrides CollectionView.Contains(Object).)
Public method CopyTo Copies the elements of the collection to an array, starting at a particular array index.
Public method DeferRefresh Enters a defer cycle that you can use to merge changes to the view and delay automatic refresh. (Overrides CollectionView.DeferRefresh().)
Public method Equals(Object) Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
Protected method Finalize Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Protected method GetEnumerator Returns an object that you can use to enumerate the items in the view. (Inherited from CollectionView.)
Public method GetHashCode Serves as a hash function for a particular type. (Inherited from Object.)
Public method GetItemAt Returns the item at the specified zero-based index in this view. (Overrides CollectionView.GetItemAt(Int32).)
Public method GetType Gets the Type of the current instance. (Inherited from Object.)
Public method IndexOf Returns the index in this collection where the specified item is located. (Overrides CollectionView.IndexOf(Object).)
Public method Insert Inserts an element into the collection at the specified index.
Protected method MemberwiseClone Creates a shallow copy of the current Object. (Inherited from Object.)
Public method MoveCurrentTo Sets the specified item in the collection as the CurrentItem. (Overrides CollectionView.MoveCurrentTo(Object).)
Public method MoveCurrentToFirst Sets the first item in the view as the CurrentItem. (Overrides CollectionView.MoveCurrentToFirst().)
Public method MoveCurrentToLast Sets the last item in the view as the CurrentItem. (Overrides CollectionView.MoveCurrentToLast().)
Public method MoveCurrentToNext Sets the item after the CurrentItem in the view as the CurrentItem. (Overrides CollectionView.MoveCurrentToNext().)
Public method MoveCurrentToPosition Sets the item at the specified index to be the CurrentItem in the view. (Overrides CollectionView.MoveCurrentToPosition(Int32).)
Public method MoveCurrentToPrevious Sets the item before the CurrentItem in the view as the CurrentItem. (Overrides CollectionView.MoveCurrentToPrevious().)
Protected method OKToChangeCurrent Returns a value that indicates whether the view can change which item is the CurrentItem. (Inherited from CollectionView.)
Protected method OnBeginChangeLogging Called by the base class to notify the derived class that an INotifyCollectionChanged.CollectionChanged event has been posted to the message queue. (Inherited from CollectionView.)
Protected method OnCollectionChanged(NotifyCollectionChangedEventArgs) Raises the CollectionChanged event. (Inherited from CollectionView.)
Protected method OnCollectionChanged(Object, NotifyCollectionChangedEventArgs) Raises the CollectionChanged event. (Inherited from CollectionView.)
Protected method OnCurrentChanged Raises the CurrentChanged event. (Inherited from CollectionView.)
Protected method OnCurrentChanging() Raises a CurrentChanging event that is not cancelable. (Inherited from CollectionView.)
Protected method OnCurrentChanging(CurrentChangingEventArgs) Raises the CurrentChanging event with the specified arguments. (Inherited from CollectionView.)
Protected method OnPropertyChanged Raises the PropertyChanged event using the specified arguments. (Inherited from CollectionView.)
Public method PassesFilter Returns a value that indicates whether the specified item belongs to this view. (Overrides CollectionView.PassesFilter(Object).)
Protected method ProcessCollectionChanged When overridden in a derived class, processes a single change on the UI thread. (Inherited from CollectionView.)
Public method Refresh Re-creates the view. (Inherited from CollectionView.)
Protected method RefreshOrDefer Refreshes the view or specifies that the view needs to be refreshed when the defer cycle completes. (Inherited from CollectionView.)
Protected method RefreshOverride Re-creates the view. (Inherited from CollectionView.)
Public method Remove Removes the specified item reference from the collection or view.
Public method RemoveAt Removes the item at the specified index of the collection or view.
Protected method SetCurrent(Object, Int32) Sets the specified item and index as the values of the CurrentItem and CurrentPosition properties. (Inherited from CollectionView.)
Protected method SetCurrent(Object, Int32, Int32) Sets the specified item and index as the values of the CurrentItem and CurrentPosition properties. This method can be called from a constructor of a derived class. (Inherited from CollectionView.)
Public method ToString Returns a string that represents the current object. (Inherited from Object.)
Public method VerifyAccess Enforces that the calling thread has access to this DispatcherObject. (Inherited from DispatcherObject.)
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  Name Description
Protected event CollectionChanged Occurs when the view has changed. (Inherited from CollectionView.)
Public event CurrentChanged Occurs after the CurrentItem has changed. (Inherited from CollectionView.)
Public event CurrentChanging Occurs when the CurrentItem is changing. (Inherited from CollectionView.)
Protected event PropertyChanged Occurs when a property value has changed. (Inherited from CollectionView.)
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  Name Description
Public Extension Method AsParallel Enables parallelization of a query. (Defined by ParallelEnumerable.)
Public Extension Method AsQueryable Converts an IEnumerable to an IQueryable. (Defined by Queryable.)
Public Extension Method Cast<TResult> Converts the elements of an IEnumerable to the specified type. (Defined by Enumerable.)
Public Extension Method OfType<TResult> Filters the elements of an IEnumerable based on a specified type. (Defined by Enumerable.)
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  Name Description
Explicit interface implemetation Private property ICollection.IsSynchronized This member supports the Windows Presentation Foundation (WPF) infrastructure and is not intended to be used directly from your code.
Explicit interface implemetation Private property ICollection.SyncRoot This member supports the Windows Presentation Foundation (WPF) infrastructure and is not intended to be used directly from your code.
Explicit interface implemetation Private method IEditableCollectionView.AddNew Adds a new item to the collection.
Explicit interface implemetation Private property IEditableCollectionView.CanAddNew Gets a value that indicates whether a new item can be added to the collection.
Explicit interface implemetation Private property IEditableCollectionView.CanCancelEdit Gets a value that indicates whether the collection view can discard pending changes and restore the original values of an edited object.
Explicit interface implemetation Private method IEditableCollectionView.CancelEdit Ends the edit transaction and, if possible, restores the original value to the item.
Explicit interface implemetation Private method IEditableCollectionView.CancelNew Ends the add transaction and discards the pending new item.
Explicit interface implemetation Private property IEditableCollectionView.CanRemove Gets a value that indicates whether an item can be removed from the collection.
Explicit interface implemetation Private method IEditableCollectionView.CommitEdit Ends the edit transaction and saves the pending changes.
Explicit interface implemetation Private method IEditableCollectionView.CommitNew Ends the add transaction and saves the pending new item.
Explicit interface implemetation Private property IEditableCollectionView.CurrentAddItem Gets the item that is being added during the current add transaction.
Explicit interface implemetation Private property IEditableCollectionView.CurrentEditItem Gets the item in the collection that is being edited.
Explicit interface implemetation Private method IEditableCollectionView.EditItem Begins an edit transaction of the specified item.
Explicit interface implemetation Private property IEditableCollectionView.IsAddingNew Gets a value that indicates whether an add transaction is in progress.
Explicit interface implemetation Private property IEditableCollectionView.IsEditingItem Gets a value that indicates whether an edit transaction is in progress.
Explicit interface implemetation Private property IEditableCollectionView.NewItemPlaceholderPosition Gets or sets the position of the new item placeholder in the collection view.
Explicit interface implemetation Private method IEditableCollectionView.Remove Removes the specified item from the collection.
Explicit interface implemetation Private method IEditableCollectionView.RemoveAt Removes the item at the specified position from the collection.
Explicit interface implemetation Private method IEditableCollectionViewAddNewItem.AddNewItem Adds the specified object to the collection.
Explicit interface implemetation Private property IEditableCollectionViewAddNewItem.CanAddNewItem Gets a value that indicates whether a specified object can be added to the collection.
Explicit interface implemetation Private method IEnumerable.GetEnumerator Returns an IEnumerator object that you can use to enumerate the items in the view. (Inherited from CollectionView.)
Explicit interface implemetation Private property IItemProperties.ItemProperties Gets a collection that contains information about the properties that are available on the items in a collection.
Explicit interface implemetation Private property IList.IsFixedSize This member supports the Windows Presentation Foundation (WPF) infrastructure and is not intended to be used directly from your code.
Explicit interface implemetation Private property IList.IsReadOnly This member supports the Windows Presentation Foundation (WPF) infrastructure and is not intended to be used directly from your code.
Explicit interface implemetation Private event INotifyCollectionChanged.CollectionChanged Occurs when the view has changed. (Inherited from CollectionView.)
Explicit interface implemetation Private event INotifyPropertyChanged.PropertyChanged Occurs when a property value changes. (Inherited from CollectionView.)
Explicit interface implemetation Private method IWeakEventListener.ReceiveWeakEvent Receives events from the centralized event manager.
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ItemCollection maintains a collection of items such as strings, objects, XML nodes, elements, and other collections. An ItemsControl uses the data in the ItemCollection to generate its content. If you want to aggregate more than one collection, assign a CompositeCollection to the ItemsSource property of your ItemsControl.

Use either the Items property or the ItemsSource property to specify the collection that should be used to generate the content of your ItemsControl. When the ItemsSource property is set, the Items collection will be made read-only and fixed-size. This means that if you are using the ItemsSource property, you cannot add, delete, or change items in the ItemCollection directly.

ItemCollection is a CollectionView and therefore provides collection view functionalities, such as sorting, grouping, and filtering. For more information, see SortDescriptions, Filter, and GroupDescriptions.

For more information about collection views, see Data Binding Overview.

If you have an ItemsControl, such as a ListBox that has content, you can use the Items property to access the ItemCollection, which is a view. Because it is a view, you can then use the view-related functionalities such as sorting, filtering, and grouping. Note that when ItemsSource is set, the view operations delegate to the view over the ItemsSource collection. Therefore, the ItemCollection supports sorting, filtering, and grouping only if the delegated view supported them.

The following example shows how to sort the content of a ListBox named myListBox. In this example, Content is the name of the property to sort by.

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myListBox.Items.SortDescriptions.Add(
    new SortDescription("Content", ListSortDirection.Descending));

When you do this, the view might or might not be the default view, depending on how the data is set up on your ItemsControl. For example, when the ItemsSource property is bound to a CollectionViewSource, the view that you obtain using the Items property is not the default view.

If your ItemsControl is bound (you are using the ItemsSource property), then you can do the following to get the default view:

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CollectionView myView;


...


myView = (CollectionView)CollectionViewSource.GetDefaultView(myItemsControl.ItemsSource);

Alternately, you can specify filtering, sorting, and grouping criteria in XAML using CollectionViewSource.

.NET Framework

Supported in: 4, 3.5, 3.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
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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