Provides a built-in collection list for storing listeners for a WeakEventManager.
Assembly: WindowsBase (in WindowsBase.dll)
XMLNS for XAML: http://schemas.microsoft.com/winfx/2006/xaml/presentation, http://schemas.microsoft.com/netfx/2007/xaml/presentation
Thetype exposes the following members.
|Add||Adds a listener item to the .|
|BeginUse||Declares the list to be in use. This prevents direct changes to the list during iterations of the list items.|
|Clone||Creates a modifiable clone of this , making deep copies of the values.|
|EndUse||Unlocks the locked state initiated by BeginUse.|
|Equals(Object)||Determines whether the specified Object is equal to the current Object. (Inherited from Object.)|
|Finalize||Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)|
|GetHashCode||Serves as a hash function for a particular type. (Inherited from Object.)|
|GetType||Gets the Type of the current instance. (Inherited from Object.)|
|MemberwiseClone||Creates a shallow copy of the current Object. (Inherited from Object.)|
|PrepareForWriting||Checks to see whether the provided list is in use, and if so, sets the list reference parameter to a copy of that list rather than the original.|
|Purge||Removes all entries from the list where the underlying reference target is a null reference.|
|Remove||Removes the first occurrence of a listener item from the .|
|ToString||Returns a string that represents the current object. (Inherited from Object.)|
Most WeakEventManager derived classes do not need to use any members on . The WeakEventManager methods ProtectedAddListener and ProtectedRemoveListener use a default internally, one list for each source.
You only need to call methods if your WeakEventManager class maintains multiple lists for the same event-source combination, with each list created to account for different conditions of the event. In this case, you would not use ProtectedAddListener and ProtectedRemoveListener and would instead implement AddListener or RemoveListener to act upon listeners in just one of the internal listener lists, typically based on a parameter that you add to AddListener or RemoveListener. Also, the handler implementation that receives the raw event cannot simply call DeliverEvent; you must instead keep track of the specifics of the event and deliver the event only to the appropriate list using DeliverEventToList.
The various methods of are provided so that you can work with your internal lists and so that you can prevent modification of the list during actual delivery of the event.
An example class that used this implementation technique is PropertyChangedEventManager, which maintains separate listener lists for PropertyChanged based on which property changed.
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