Hi Daniel,
That does help! A few more questions in that case:
1) Where should I store "d"? Can it be a property of the class myClass?
2) If I am registering a callback (using a declare), should I pass d as a
ptr into the declare? Or something else? I guess I'm not looking to invoke
the delegate myself, but rather to have it called from a callback.
Thanks for the help,
Dave.
> From: Daniel Stenning <d0stenning at msn dot com>
> Reply-To: REALbasic NUG <realbasic-nug at lists dot realsoftware dot com>
> Date: Fri, 30 Nov 2007 21:34:41 +0000
> To: "REALbasic NUG <realbasic-nug at lists dot realsoftware dot com>"
> <realbasic-nug at lists dot realsoftware dot com>
> Conversation: Some questions about delegates
> Subject: Re: 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.
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>
> Cheers,
> Dan
>
>
>
>
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