This simple article shows that creating a weak event (an event that allows objects who respond to it to be collected) is really simple with the help of the
I created this class when I discovered a stupid bug (but, one that can turn to be a serious problem) in my other article. Classes that registered themselves in
GCUtils.Collected where not allowed to be collected themselves if they didn't unregister from the event. It must be a weak event, so I did it, and created a class that helps this process.
Using the code
To create a weak event, you must create a
WeakDelegateSet, and must redirect the add and remove handlers of the event to that
WeakDelegateSet. For example:
private WeakDelegateSet fMyWeakEvent = new WeakDelegateSet();
public event EventHandler MyWeakEvent
And then, you invoke the event using the
Invoke method in the
WeakDelegateSet, passing all the required parameters to it. So, for my example event:
This is all that is needed to create a weak event. Maybe this is not a very common requirement, but I needed the weak event to be able to collect objects that were registered for the
Collected event in case
Dispose was not invoked. And, I am sure many events may use this as many times we need to be informed of something when the object is really alive.
I started to program computers when I was 11 years old, as a hobbist, programming in AMOS Basic and Blitz Basic for Amiga.
At 12 I had my first try with assembler, but it was too difficult at the time. Then, in the same year, I learned C and, after learning C, I was finally able to learn assembler (for Motorola 680x0).
Not sure, but probably between 12 and 13, I started to learn C++. I always programmed "in an object oriented way", but using function pointers instead of virtual methods.
At 15 I started to learn Pascal at school and to use Delphi. At 16 I started my first internship (using Delphi). At 18 I started to work professionally using C++ and since then I've developed my programming skills as a professional developer in C++ and C#, generally creating libraries that help other developers do they work easier, faster and with less errors.
Want more info or simply want to contact me?
Take a look at: http://paulozemek.azurewebsites.net/
Or e-mail me at: firstname.lastname@example.org
Codeproject MVP 2012
Microsoft MVP 2013