 |
 | Home | Contact Us | FAQ | Search & Site Map | Link to Us |
 | Sign In | Join | Other 45 Sites in Network |
.NET Forum / Languages / C# / November 2006What keeps track of delegates?
If I have multiple subscribers to a delegate, what keeps track of them? Are they out there on the heap? When I declare a delegate: public delegate void MyDelegate (object myObject, MyObjectEventArgs myEvent); public MyDelegate SomethingHappened; and later I have two subscribers, what's going on in the background. My Delegate "variable," if that is what it's called just looks like a variable, but behind the scenes it can hold multiple instances of subscribers, correct, like an array? Just wondered what was going on. I'm "protected" from it by the .Net framework. Thanks. > If I have multiple subscribers to a delegate, what keeps track of them? > Are they out there on the heap? [quoted text clipped - 10 lines] > subscribers, correct, like an array? Just wondered what was going on. > I'm "protected" from it by the .Net framework. I don't know the answer difinitively, but since it appears to be a classic observer pattern, it is like a collection of delegate (class) instances on the object being observed. Thus, if you listen to the events on a form, the delegate instances are part of the form instance. THat is why it is good practice to unregister your events when you are no longer interested in listening for them. Perhaps somebody else will answer more definitively.  SignatureThomas T. Veldhouse Key Fingerprint: D281 77A5 63EE 82C5 5E68 00E4 7868 0ADC 4EFB 39F0 The System.Delegate class from which your delegate inherits maintains an invocation list for a delegate -- a list of methods that will be called when the delegate is invoked. When you invoke the delegate, the base class implementation loops through the list and calls each method. Peter SignatureCo-founder, Eggheadcafe.com developer portal: http://www.eggheadcafe.com UnBlog: http://petesbloggerama.blogspot.com > If I have multiple subscribers to a delegate, what keeps track of them? > Are they out there on the heap? [quoted text clipped - 12 lines] > > Thanks. Hi Peter, More accurately, it's the MulticastDelegate class, which derives from Delegate, that provides the invocation list. SignatureDave Sexton > The System.Delegate class from which your delegate inherits maintains an > invocation list for a delegate -- a list of methods that will be called when [quoted text clipped - 21 lines] >> >> Thanks. And by default, they are executed syncronous and in list order. You can invoke them yourself on a seperate threads if that is something you need. SignatureWilliam Stacey [C# MVP] | Hi Peter, | [quoted text clipped - 26 lines] | >> | >> Thanks. In the delegates samples section of the .Net 1.1 framework SDK there's a chat sample that manually calls methods from the invocation list. It's a great tutorial on this topic. On my PC, the sample is at C:\Program Files\Microsoft Visual Studio .NET 2003\SDK\v1.1\Samples\Technologies\DelegatesAndEvents\cs I point that out because there are other chat samples in the SDK that do not use the same technology. Dale SignatureDale Preston MCAD C# MCSE, MCDBA > And by default, they are executed syncronous and in list order. You can > invoke them yourself on a seperate threads if that is something you need. [quoted text clipped - 31 lines] > | >> > | >> Thanks. Free MagazinesGet these publications absolutely FREE for up to 12 months. There are no hidden fees and no obligation. Simply choose a title, complete the application form and submit it. Read more ...
|
Reply to this Message
|
 Sign In
 Join
 My Latest Posts My Monitored Threads My Blog My Photo Gallery My Profile My Homepage Start New Thread Enable EMail Alerts Rate this Thread
|
©2008 Advenet LLC Privacy Policy - Terms of Use
This website includes both content owned or controlled by Advenet as well as content owned or controlled by third parties.