Serviced Componentsand COM+

[JohnFol]

I have a piece of code that I want to use as a library / dll for other s/w
developments.

For example in VB6 land,
1) I create MyCalculator.DL L
2) In another project I make a reference to MyCalculator.DL L
3) I then do something like
Dim objMaths as MyCalculator.Ma thsFunctions
:
4) When I want to release the object I simply do
Set objMaths = Nothing

This code will work regardless of MyCalculator.DL L being hosted in Component
Services or not.

Now, using VB.Net I do
1) I create MyCalculator.DL L (with the class Inheriting ServicedCompone nt)
2) In another project I make a reference to MyCalculator.DL L
3) I then do something like
Dim objMaths as MyCalculator.Ma thsFunctions
:
But now, to release the component I understand I need to use 1 of 2 methods
depedning on how the DLL is hosted. ie

objMaths.Dispos e (for a std DLL)
or ServicedCompone nt.DisposeObjec t (objMaths) if it is hosted in
Component Services


Is this correct, and if so, why should my "client" s/w need to be coded
specifically for how the DLL is deployed?

[Paul Clement]

Re: Serviced Componentsand COM+

On Mon, 25 Apr 2005 09:13:09 GMT, "JohnFol" <OutlookExpress @WibbleObbble.C om> wrote:

¤ I have a piece of code that I want to use as a library / dll for other s/w
¤ developments.
¤
¤ For example in VB6 land,
¤ 1) I create MyCalculator.DL L
¤ 2) In another project I make a reference to MyCalculator.DL L
¤ 3) I then do something like
¤ Dim objMaths as MyCalculator.Ma thsFunctions
¤ :
¤ 4) When I want to release the object I simply do
¤ Set objMaths = Nothing
¤
¤ This code will work regardless of MyCalculator.DL L being hosted in Component
¤ Services or not.
¤
¤ Now, using VB.Net I do
¤ 1) I create MyCalculator.DL L (with the class Inheriting ServicedCompone nt)
¤ 2) In another project I make a reference to MyCalculator.DL L
¤ 3) I then do something like
¤ Dim objMaths as MyCalculator.Ma thsFunctions
¤ :
¤ But now, to release the component I understand I need to use 1 of 2 methods
¤ depedning on how the DLL is hosted. ie
¤
¤ objMaths.Dispos e (for a std DLL)
¤ or ServicedCompone nt.DisposeObjec t (objMaths) if it is hosted in
¤ Component Services
¤
¤
¤ Is this correct, and if so, why should my "client" s/w need to be coded
¤ specifically for how the DLL is deployed?

Because when using COM+ there is an associated object that is created when hosting the managed code
DLL. If this object is not released it will continue to exist under COM+.

Not sure if there is a way to determine whether a .NET DLL is running under COM+ in order to
determine which Dispose method to use. GetObjectContex t will do this when using the COM+ objects.


Paul
~~~~
Microsoft MVP (Visual Basic)