Delegates and assigning multiple procedures? How?

[Iced Crow]

In C# I know that you can use delegates to assing
multiple addresses of sub and functions to a delegate and
have it fire multiple procedures...

How do I do this in VB? I only know of assigning a
single method to a delegate in VB.NET. I want to use it
as in C#... to fire multiple events.

Thanks in advance!

[Herfried K. Wagner [MVP]]

Hello,

"Iced Crow" <ch********@aol .com> schrieb:

In C# I know that you can use delegates to assing
multiple addresses of sub and functions to a delegate and
have it fire multiple procedures...

How do I do this in VB? I only know of assigning a
single method to a delegate in VB.NET. I want to use it
as in C#... to fire multiple events.

Are you sure you read this chapter of the documentation?

Events and Delegates (Visual Basic Language Concepts)
http://msdn.microsoft.com/library/en...nheritance.asp

--
Herfried K. Wagner
MVP · VB Classic, VB.NET
http://www.mvps.org/dotnet

[Chris Nye]

Those examples only show how to add a single method to a delegate...
what method of a delegate can I call to add multiple methods? Do I have
to create an array of delegates or a collection of delegates? The only
thing close to what I need is "CreateDelegate " but that is asking for a
type...

*** Sent via Developersdex http://www.developersdex.com ***
Don't just participate in USENET...get rewarded for it!

[IcedCrow]

I glanced through it but could not find an instance of
applying multiple methods to a single delegate, only how
to add a single method to a delegate which i already know
how to do...

[Jay B. Harlow [MVP - Outlook]]

Iced Crow,
Are you talking actual delegates or are you talking events? As Herfried
pointed you at how to use AddHandler to add multiple subs to an event so
they all get called.

If you are talking actual delegates:

Have you tried the Delegate.Combin e method that concatenates the invocations
lists of two delegates together?

Hope this helps
Jay

"Iced Crow" <ch********@aol .com> wrote in message
news:79******** *************** *****@phx.gbl.. .

In C# I know that you can use delegates to assing
multiple addresses of sub and functions to a delegate and
have it fire multiple procedures...

How do I do this in VB? I only know of assigning a
single method to a delegate in VB.NET. I want to use it
as in C#... to fire multiple events.

Thanks in advance!

[IcedCrow]

Greetings Jay,

No I am not talking about events, I understand how to add
handlers.

I am talking delegates. A delegate object being assigned
the address of a procedure and then having it's invoke
method called to fire that procedure.

In C# I know of how to take a single delegate and assign
to it calls from multiple procedures, so that I only have
to fire off a single INVOKE method from that single
delegate to fire off the multiple methods.

With VB.NET I only know of how to assign a single method
address to a single delegate.

I understand the combine function, but I'm only working
with one delegate here so there's nothing to combine. Do
I have to create multiple delegate objects that reference
methods and then combine them all? THat seems horribly
ineffecient...

I don't know how familiar you are with the MOCs but in
the 2124 C# course they have an example with a nuclear
power plant and one invoke call to a delegate is able to
fire off multiple calls to pump procedures.

This is what I want to do with Visual Basic.NET. It has
nothing to do with events.

Thanks!

[Jay B. Harlow [MVP - Outlook]]

IcedCrow.

I understand the combine function, but I'm only working
with one delegate here so there's nothing to combine. Do
I have to create multiple delegate objects that reference
methods and then combine them all? THat seems horribly
ineffecient... How are you combining them in C#?

Is it the += syntax the same as for events?

(I don't do a lot of C#, but will look it up).

Thanks
Jay

"IcedCrow" <ch********@aol .com> wrote in message
news:00******** *************** *****@phx.gbl.. . Greetings Jay,

No I am not talking about events, I understand how to add
handlers.

I am talking delegates. A delegate object being assigned
the address of a procedure and then having it's invoke
method called to fire that procedure.

In C# I know of how to take a single delegate and assign
to it calls from multiple procedures, so that I only have
to fire off a single INVOKE method from that single
delegate to fire off the multiple methods.

With VB.NET I only know of how to assign a single method
address to a single delegate.

I understand the combine function, but I'm only working
with one delegate here so there's nothing to combine. Do
I have to create multiple delegate objects that reference
methods and then combine them all? THat seems horribly
ineffecient...

I don't know how familiar you are with the MOCs but in
the 2124 C# course they have an example with a nuclear
power plant and one invoke call to a delegate is able to
fire off multiple calls to pump procedures.

This is what I want to do with Visual Basic.NET. It has
nothing to do with events.

Thanks!

[Fergus Cooney]

Howdy Iced,

The Help doc that Herfried gave says:

Event delegates are multicast, which means that they can hold references
to more than one event handling method. For details, see Delegate

The AddHandler statement that Jay mentions:
See VB Language/VB Language Tour/OOP in VB/Events and Delegates

The AddHandler statement is similar to the Handles clause in that both allow
you to specify an event handler that will handle an event. However, AddHandler
along with RemoveHandler provide greater flexibility than the Handles clause,
allowing you to dynamically add, remove, and change the error handler
associated with an event. And unlike Handles, AddHandler allows you to
associate multiple event handlers with a single event.

AddHandler takes two arguments: the name of an event from an event sender such
as a control, and an expression that evaluates to a delegate. You do not need
to explicitly specify the delegate class when using AddHandler, since the
AddressOf statement always returns a reference to the delegate.

The following example associates an event handler with an event raised by an
object:
AddHandler MyObject.Event1 , AddressOf Me.MyEventHandl er

RemoveHandler, which disconnects an event from an event handler, uses the same
syntax as AddHandler. For example:
RemoveHandler MyObject.Event1 , AddressOf Me.MyEventHandl er

Regards,
Fergus
MVP [Windows Start button, Shutdown dialogue]

[Jay B. Harlow [MVP - Outlook]]

IcedCrow,

I understand the combine function, but I'm only working
with one delegate here so there's nothing to combine. Do
I have to create multiple delegate objects that reference
methods and then combine them all? THat seems horribly
ineffecient... You do realize that the "+=" operator in C# when used with delegate types is
shorthand for the Delegate.Combin e function?

While the "-=" operator when used with delegate types is shorthand for
Delegate.Remove function?

You can use ildasm.exe to verify the above statement.

So as I stated, have you tried the Delegate.Combin e function?

Further you do realize that each time you use the AddressOf operator in
VB.NET that you are given a new Delegate?

Hope this helps
Jay

"IcedCrow" <ch********@aol .com> wrote in message
news:00******** *************** *****@phx.gbl.. . Greetings Jay,

No I am not talking about events, I understand how to add
handlers.

I am talking delegates. A delegate object being assigned
the address of a procedure and then having it's invoke
method called to fire that procedure.

In C# I know of how to take a single delegate and assign
to it calls from multiple procedures, so that I only have
to fire off a single INVOKE method from that single
delegate to fire off the multiple methods.

With VB.NET I only know of how to assign a single method
address to a single delegate.

I understand the combine function, but I'm only working
with one delegate here so there's nothing to combine. Do
I have to create multiple delegate objects that reference
methods and then combine them all? THat seems horribly
ineffecient...

I don't know how familiar you are with the MOCs but in
the 2124 C# course they have an example with a nuclear
power plant and one invoke call to a delegate is able to
fire off multiple calls to pump procedures.

This is what I want to do with Visual Basic.NET. It has
nothing to do with events.

Thanks!

[steve]

yes it is +=
"Jay B. Harlow [MVP - Outlook]" <Ja********@ema il.msn.com> wrote in message
news:eg******** ******@TK2MSFTN GP12.phx.gbl...

IcedCrow.

I understand the combine function, but I'm only working
with one delegate here so there's nothing to combine. Do
I have to create multiple delegate objects that reference
methods and then combine them all? THat seems horribly
ineffecient...

How are you combining them in C#?

Is it the += syntax the same as for events?

(I don't do a lot of C#, but will look it up).

Thanks
Jay

"IcedCrow" <ch********@aol .com> wrote in message
news:00******** *************** *****@phx.gbl.. .

Greetings Jay,

No I am not talking about events, I understand how to add
handlers.

I am talking delegates. A delegate object being assigned
the address of a procedure and then having it's invoke
method called to fire that procedure.

In C# I know of how to take a single delegate and assign
to it calls from multiple procedures, so that I only have
to fire off a single INVOKE method from that single
delegate to fire off the multiple methods.

With VB.NET I only know of how to assign a single method
address to a single delegate.

I understand the combine function, but I'm only working
with one delegate here so there's nothing to combine. Do
I have to create multiple delegate objects that reference
methods and then combine them all? THat seems horribly
ineffecient...

I don't know how familiar you are with the MOCs but in
the 2124 C# course they have an example with a nuclear
power plant and one invoke call to a delegate is able to
fire off multiple calls to pump procedures.

This is what I want to do with Visual Basic.NET. It has
nothing to do with events.

Thanks!