MultiCastDelegate

Hi,

Delegates are internally classes which the compiler generates. These
classes derive from System.Delegate (if there the delegate has a return
value) or System.MulticastDelegate (if there are no return values).

You are not supposed to use these classes in your code.

Let me know if you need more assistance.

HTH,
Rakesh Rajan

"MB" wrote:

Hi,

I got following :

' This delegate is declared as a void, so the compiler automatically
' generates a new class, named CheckAndPrintDelegate, that inherits from
' System.MulticastDelegate

from :
http://msdn.microsoft.com/library/de...us/cpref/html/
frlrfSystemMulticastDelegateClassTopic.asp

But how do you inherit from a multicast delegate ?
When I try this, I get following error: cannot inherit from special class
'System.MulticastDelegate'

Don't understand that multicast thingy all to good :)

thanks

Nov 16 '05 #2

delegates *always* derive from System.MulticastDelegate whether they have a return type or not. When you fire a delegate that has a return type and has multiple targets you only see the result from the last invocation. To see all the results you have to process the calls manually via GetInvocationList()

Regards

Richard Blewett - DevelopMentor
http://www.dotnetconsult.co.uk/weblog
http://www.dotnetconsult.co.uk

Hi,

Delegates are internally classes which the compiler generates. These
classes derive from System.Delegate (if there the delegate has a return
value) or System.MulticastDelegate (if there are no return values).

You are not supposed to use these classes in your code.

Let me know if you need more assistance.

HTH,
Rakesh Rajan

Nov 16 '05 #3

Hi Richard,

I agree that this is indeed the case as is evident in the IL.

But ideally, I don't feel this should be the case. I feel that it should be
the way as described in the MSDN page @
http://msdn.microsoft.com/library/de...ClassTopic.asp

But for some reason, it seems it is not as is documented.

HTH,
Rakesh Rajan

"Richard Blewett [DevelopMentor]" wrote:

delegates *always* derive from System.MulticastDelegate whether they have a return type or not. When you fire a delegate that has a return type and has multiple targets you only see the result from the last invocation. To see all the results you have to process the calls manually via GetInvocationList()

Regards

Richard Blewett - DevelopMentor
http://www.dotnetconsult.co.uk/weblog
http://www.dotnetconsult.co.uk

Hi,

Delegates are internally classes which the compiler generates. These
classes derive from System.Delegate (if there the delegate has a return
value) or System.MulticastDelegate (if there are no return values).

You are not supposed to use these classes in your code.

Let me know if you need more assistance.

HTH,
Rakesh Rajan

Nov 16 '05 #4

There were two types of delegates in beta 1 of 1.0 but then they realised a single target delegate was really only a multicast delegate with only one entry in its invocation list and so simplified the model to what you see today.

Regards

Richard Blewett - DevelopMentor
http://www.dotnetconsult.co.uk/weblog
http://www.dotnetconsult.co.uk

Hi Richard,

I agree that this is indeed the case as is evident in the IL.

But ideally, I don't feel this should be the case. I feel that it should be
the way as described in the MSDN page @: http://msdn.microsoft.com/library/de...ClassTopic.asp

But for some reason, it seems it is not as is documented.

HTH,
Rakesh Rajan

Nov 16 '05 #5

Hi,

Thanks Richard, for the extra info.

Hmm...so shouldn't they be updating the documentation?

Regards,
Rakesh Rajan

"Richard Blewett [DevelopMentor]" wrote:

There were two types of delegates in beta 1 of 1.0 but then they realised a single target delegate was really only a multicast delegate with only one entry in its invocation list and so simplified the model to what you see today.

Regards

Richard Blewett - DevelopMentor
http://www.dotnetconsult.co.uk/weblog
http://www.dotnetconsult.co.uk

Hi Richard,

I agree that this is indeed the case as is evident in the IL.

But ideally, I don't feel this should be the case. I feel that it should be
the way as described in the MSDN page @: http://msdn.microsoft.com/library/de...ClassTopic.asp

But for some reason, it seems it is not as is documented.

HTH,
Rakesh Rajan

Nov 16 '05 #6

I don't think the documentation is wrong - well not from my reading of it. Which passage are you refering to and how do you interpret it?

Regards

Richard Blewett - DevelopMentor
http://www.dotnetconsult.co.uk/weblog
http://www.dotnetconsult.co.uk

Hi,

Thanks Richard, for the extra info.

Hmm...so shouldn't they be updating the documentation?

Regards,
Rakesh Rajan

Nov 16 '05 #7

Hi,

It's in the source code comments they are referring to this.

Quoting it:
' This delegate is declared as a void, so the compiler automatically
' generates a new class, named CheckAndPrintDelegate, that inherits from
' System.MulticastDelegate.
' If this delegate were declared with a Boolean return value, it
' would inherit from System.Delegate and be a singlecast delegate.

Regards,
Rakesh Rajan

"Richard Blewett [DevelopMentor]" wrote:

I don't think the documentation is wrong - well not from my reading of it. Which passage are you refering to and how do you interpret it?

Regards

Richard Blewett - DevelopMentor
http://www.dotnetconsult.co.uk/weblog
http://www.dotnetconsult.co.uk

Hi,

Thanks Richard, for the extra info.

Hmm...so shouldn't they be updating the documentation?

Regards,
Rakesh Rajan

Nov 16 '05 #8

Yep - that definitely needs changing - good spot

Regards

Richard Blewett - DevelopMentor
http://www.dotnetconsult.co.uk/weblog
http://www.dotnetconsult.co.uk

Hi,

It's in the source code comments they are referring to this.

Quoting it:
' This delegate is declared as a void, so the compiler automatically
' generates a new class, named CheckAndPrintDelegate, that inherits from
' System.MulticastDelegate.
' If this delegate were declared with a Boolean return value, it
' would inherit from System.Delegate and be a singlecast delegate.

Regards,
Rakesh Rajan

Nov 16 '05 #9

by: Edward Diener | last post by:

I am surprised that a MulticastDelegate does not have a particular member function which checks if a particular delegate is in its invocation list. I can do this manually of course but a Find, or...

MultiCastDelegate vs Delegate

by: Nima | last post by:

The documentation for the Delegate and the MultiCastDelegate classes tell me that when we have a line like: public delegate void CheckAndPrintDelegate(string str); it causes the compiler to...

MulticastDelegate return value

by: SW Prathap | last post by:

hi how to capture return value of MulticastDelegate. swp

casting event handlers

by: Darren | last post by:

Why can I cast an event I declare but not one defined in the Form class public event System.EventHandler MyEvent; private void SomeFn() { MulticastDelegate d1 =...

Does delegate instantiate an instance of Delegate or MultiCastDele

by: Nima | last post by:

The documentation for the Delegate and the MultiCastDelegate classes tell me that when we have a line like: public delegate void CheckAndPrintDelegate(string str); it causes the compiler to...

Adding delegates via +=

by: Edward Diener | last post by:

Does the += notation for adding delegates to a delegate pointer object work even if the delegate pointer is 0 ? As an example: __gc class SomeObjectClass { public: void SomeObjectMethod() { } };...

Delegate comparisons

by: Quimbly | last post by:

I'm having some problems comparing delegates. In all sample projects I create, I can't get the problem to occur, but there is definitely a problem with my production code. I can't give all the...

Advanced use of delegates to automatically disconnect delegates from a set of events

by: kristian.freed | last post by:

Hi, I currently work in a project written fully in C# where we make extensive use of delegates and events. We have a model where a "state", an object holding data but not much code but which...

Delegates are useful, and here is why (sample program)

by: raylopez99 | last post by:

They usually don't teach you in most textbooks I've seen that delegates can be used to call class methods from classes that are 'unaware' of the delegate, so long as the class has the same...