Class WeakEventController

Implements a weak event listener that allows the owner to be garbage collected if it is the only remaining link is an event handler.

Inheritance

object

WeakEventController

Namespace: Neon.Common

Assembly: Neon.Common.dll

Syntax

public static class WeakEventController

Remarks

This class is intended to be a drop-in replacement for the WeakEventManager class that is available in .NET 4.5 but is not currently present in the Xamarin Mono class libraries. Use the AddHandler<TEventSource, TEventArgs>(TEventSource, string, EventHandler<TEventArgs>) and RemoveHandler<TEventSource, TEventArgs>(TEventSource, string, EventHandler<TEventArgs>) to add or remove event handlers.

note

Important: Take care to remove any handlers when an event listener instance is disposed and/or finalized. Neglecting to do this will orhpan the objects WeakEventController uses to track the handler references.

This code was adapted from a Code Project article by Samuel Cragg called WeakEventManager for WinRT. The code is licensed under the The Code Project Open License (CPOL).

I enhanced the code by making it threadsafe.

Methods

AddHandler<TEventSource, TEventArgs>(TEventSource, string, EventHandler<TEventArgs>)

Adds the specified event handler to the specified event.

Declaration

public static void AddHandler<TEventSource, TEventArgs>(TEventSource source, string eventName, EventHandler<TEventArgs> handler)

Parameters

Type	Name	Description
TEventSource	source	The source object that raises the specified event or null.
string	eventName	The name of the event to subscribe to.
EventHandler<TEventArgs>	handler	The delegate that handles the event.

Type Parameters

Name	Description
TEventSource	The type that raises the event.
TEventArgs	The type that holds the event data.

RemoveHandler<TEventSource, TEventArgs>(TEventSource, string, EventHandler<TEventArgs>)

Removes the specified event handler from the specified event.

Declaration

public static void RemoveHandler<TEventSource, TEventArgs>(TEventSource source, string eventName, EventHandler<TEventArgs> handler)

Parameters

Type	Name	Description
TEventSource	source	The source object that raises the specified event, or null if it's a static event.
string	eventName	The name of the event to remove the handler from.
EventHandler<TEventArgs>	handler	The delegate to remove.

Type Parameters

Name	Description
TEventSource	The type that raises the event.
TEventArgs	The type that holds the event data.