WeakEventHandler Class

Mediates an EventHandler event, holding only a weak reference to the event sink, and a weak reference to the event source for removing the event handler. Thus there is no reference created from the event source to the event sink, and both the event sink and the event source can be garbage collected.

Inheritance Hierarchy

SystemObject
AltaxoWeakEventHandler

Namespace: Altaxo
Assembly: AltaxoCore (in AltaxoCore.dll) Version: 4.8.3179.0 (4.8.3179.0)

Syntax

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public class WeakEventHandler

The WeakEventHandler type exposes the following members.

Constructors

	Name	Description
	WeakEventHandler(EventHandler, Object, String)	Initializes a new instance of the WeakEventHandler class.
	WeakEventHandler(EventHandler, Type, String)	Initializes a new instance of the WeakActionHandler class for a static event.

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Properties

	Name	Description
	EventSource	Gets the event source. Attention! Use the returned value only locally, otherwise, you will get a strong reference that you wanted to avoid.

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Methods

	Name	Description
	Equals	Determines whether the specified object is equal to the current object. (Inherited from Object)
	EventSink	Handles the event from the original source. You must not call this method directly. However, it can be neccessary to use the method reference if the implicit casting fails. See remarks in the description of this class.
	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 the default hash function. (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)
	Remove	Removes the event handler from the event source, using the stored remove action..
	ToString	Returns a string that represents the current object. (Inherited from Object)

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Operators

	Name	Description
	(WeakEventHandler to EventHandler)	Converts this instance to an EventHandler that can be used to add or remove it from/to an event.

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Remarks

Typical use:

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source.Changed += new WeakEventHandler(this.EhHandleChange, source, nameof(source.Changed));

Sometimes it might be neccessary to explicitly use the event handler method of this instance:

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source.Changed += new WeakEventHandler(this.EhHandleChange, source, nameof(source.Changed)).EventSink;

You can even maintain a reference to the WeakActionHandler instance in your event sink instance, in case you have to remove the event handling programmatically:

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_weakEventHandler = new WeakEventHandler(this.EhHandleChange, source, nameof(source.Changed)); // weakEventHandler is an instance variable of this class
source.Changed += _weakEventHandler;
.
.
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source.Changed -= _weakEventHandler;

Reference

Altaxo Namespace