realbasic-nug
[Top] [All Lists]

Re: Some questions about delegates

To: "REALbasic NUG <realbasic-nug at lists dot realsoftware dot com>" <realbasic-nug at lists dot realsoftware dot com>
Subject: Re: Some questions about delegates
From: Daniel Stenning <d0stenning at msn dot com>
Date: Fri, 30 Nov 2007 21:34:41 +0000
Delivered-to: listarchive at realsoftware dot com
Delivered-to: realbasic-nug at lists dot realsoftware dot com
Thread-index: Acgzlmc5pYX46p+JEdycPwAbY5gHRwAAmmDc
Thread-topic: Some questions about delegates
Delegates contain a reference to the object instance that the method is on,
IF you create a delegate from a method on a class instance as opposed to
>from a shared method or global method.

First define the delegate - say called mydelegate in a module.

then if you do

Dim cinstance as New myClass
Dim d as mydelegate = AddressOf cinstance.method1

You will find that when d.Invoke(...) gets called that it will call method1
on the instance you created ( cinstance )

Hope this helps.


On 30/11/07 21:17, "Dave Addey" <listmail1 at addey dot com> wrote:

> I¹m working on my RBScript-based controller code, and it¹s all going well ­
> but I have one more challenge....
> 
> I¹ve created a generic ³Controller² class.  The code for the controller is
> in an RBscript. I want to be able to register a callback, which will call a
> callback method on a controller class instance.  I think this might be where
> I should use delegates?
> 
> Historically, I¹ve always had to use global module methods for callbacks.
> This has the downside that I don¹t know (from within the callback) which
> controller object triggered the callback.  Since my different controller
> types may need to use the same callback template (e.g. two UInt32 params,
> returning a UInt32), I won¹t even know which type of controller caused the
> callback, let alone which instance of the controller, in order to pass the
> callback event on to the controller for processing.
> 
> I¹m rather hoping that delegates give me a way to set up these callbacks
> using class-instance methods as the callback target.  But I can¹t work out
> what the code would be to do this.  Do I need to define a delegate in a
> module?  Do I need a property on the class to represent the callback method?
> Where would the callback code go?
> 
> Any help much appreciated!
> 
> Dave.
> _______________________________________________
> Unsubscribe or switch delivery mode:
> <http://www.realsoftware.com/support/listmanager/>
> 
> Search the archives:
> <http://support.realsoftware.com/listarchives/lists.html>
> 

Cheers,
Dan




_______________________________________________
Unsubscribe or switch delivery mode:
<http://www.realsoftware.com/support/listmanager/>

Search the archives:
<http://support.realsoftware.com/listarchives/lists.html>


<Prev in Thread] Current Thread [Next in Thread>