This question already has answers here:
Is it bad to not unregister event handlers?
(2 answers)
Closed 9 years ago.
There is a small event handler example at msdn
with the line:
myNewLog.EntryWritten += new EntryWrittenEventHandler(MyOnEntryWritten);
Presumably this adds the triggering event to a queue to be handled. What removes the handler from the queue? Do I even need to think about this?
The "-=" operator removes the subscriber from the publisher. Not unsubscribing is a problem when the publisher of the event will live longer than the subscriber.
More info here and here.
Related
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Understanding events and event handlers in C#
(13 answers)
Closed 4 years ago.
I am a newbie to asp.net, can you please explain the line of code below?
this.lblDelete.Click += new System.EventHandler(this.lblDelete_Click);
I don't know much about events and delegates.
Essentially the code attaches an event handler to an event so that it can be, well... handled.
A simple way to understand it would be.
This event:
this.lblDelete.Click
Has this event handler attached:
+= new System.EventHandler
Which calls this method:
lblDelete_Click
This question already has answers here:
Event declaration with assignment to empty delegate
(2 answers)
Closed 8 years ago.
I have just come across this code in a book I'm working through:
public event EventHandler<ProjectEventArgs> ProjectUpdated = delegate { };
Is setting a delegate here merely to ensure ProjectUpdated is never null, and this avoid the standard null check before firing the event?
Normally, when you are to raise an event, you have to check for null values, meaning, no event handlers attached. With this approach, you can skip this check, because the event will always have an empty handler.
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Manual editing of *.designer.cs file
(5 answers)
Closed 8 years ago.
I have a custom control and I subscribe to an event in the InitializeComponent method. Whenever I go into the designer and move the control or make any changes, the initialize component will rewrite and remove the subscription to the event. Is there any way to avoid this? I would rather not just subscribe in the Load event of the form, but I am unfamiliar with how this method gets dynamically created.
This is why you don't edit the designer code. It's specifically designed to not maintain these types of changes.
You should be subscribing to the event in the object's constructor, load event, or some similar location.
This question already has answers here:
Is it bad to not unregister event handlers?
(2 answers)
Closed 9 years ago.
I have a Winform, i have added a few controls like Textbox, buttons.
I subscribed to the textbox Changed event, teh button click event.
The designer automatically adds the += statements i.e subsribtion of events in the
designer.cs file.
My question is should we add the unregisterig of these events in the dispose function ?
is it necesssary, or will there be any leak if i do not unregister.
Or is it that .NET takes care of it.
Refers to following link:
Is it bad to not unregister event handlers?
This is not required to unregister events that is subscribed on same class.
If your WinForm is the only one that is consuming/subscribing to it, then you dont need to worry about unsub.
This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
How to correctly unregister an event handler
If I have registered an event as following
List.Changed += new ChangedEventHandler(ListChanged);
what should be the best way of de registering it in destructor
List.Changed -= new ChangedEventHandler(ListChanged);
or
List.Changed -=ListChanged;
the second option is just shorthand
The second option. And you can subscribe to it the same way:
List.Changed += ListChanged;