Class "Terminate Event"

[Wokawidget]

OK...I am going to use VB6 code here...I know, I know...but I don't know .NET off the top of my head just yet.
I have a class clsWoof

Public Class Class1
    Protected Overrides Sub Finalize()
        MsgBox("Class Terminated")
        MyBase.Finalize()
    End Sub
End Class

Ok, now I am assuming that Finalize in .NET is the same as Terminate in VB 6...am I correct in this assumption?

Now in my form I have:

Private Sub cmdWoof_Click() 'VB 6 code, but u get the idea
Dim objNew   As clsWoof
   objNew = New clsWoof
   objNew = Nothing
End Sub

OK, now I would expect the msgbox to appear when I click the button...NOT when I close my app down...I don't understand? Am I missing something really simple???

Woka (Just started .NET and is being really thick )

[lianwk]

Hi,

You are disturbing the Base Class Event. It will fire when the form event trigger.

To solve this, put it into a Sub...

[MerrionComputin]

You have to bear in mind that in the brave new world of .NET, the lifetime of a class is ended when the garbage collector comes along and scoops it up some time after your program has released all references to it. In a small program this will not occur until you shut your app down.
If you have code that you need to execute on Finalize - like releasing resources etc., then make your class implement the IDisposable interface and call the Dispose method to nuke it.

[Wokawidget]

WOT?!
So that object in the above example wont get destroyed till my app terminates??? Surely that resuklts in a memory leak!...?

So how would I implement this IDispose jobbie?

Is this such a basic question that I shouldn't be asking it, like how do I change a caption of a label in vb6???

Does anyone know of any good .NET resources for muppets like me?

Woka

[MerrionComputin]

Don't worry about memory - it is managed for you - that's what managed code means.

Good references for VB.net include the book:-
Professional VB.Net by Wrox Press (ISBN 1-861004-97-4)
and the websites:
GotDotNet and DotNetForums (I am "Merrion" on both of those btw.)

[MerrionComputin]

To implement IDisposable...

Public Class PrintJob
    Implements IDisposable
 
 
      Public Overridable Overloads Sub Dispose() Implements IDisposable.Dispose
          '\\ Do your cleaning up here....
    End Sub
End Class

[Edneeis]

You'd also then call the dispose method instead of setting it to nothing (or you can do both if really want to).

Private Sub cmdWoof_Click() 
   Dim objNew As New clsWoof
   objNew.Dispose()
End Sub

Although if you don't have any resources to clean up then there is really no need to even call dispose or implement IDisposable.

[Wokawidget]

Cheers. Will have a quick play tonight.

.NET scares the **** out of me

Woka

[MerrionComputin]

.NET scares the **** out of me

Going from VB6 to VB.Net is like going from a plastic spoon to a swiss army knife. Sure there's a lot of new things to learn but the amount of new stuff you can do totally makes up for it.

[Wokawidget]

Like what?
Anything that would be used to develop in house software?

WOka

[MerrionComputin]

New stuff that is really useful:
Managed multithreading - like:

Dim ts As New System.Threading.ThreadStart(AddressOf woofProc)
 
  Dim thread As New System.Threading.Thread(ts)
  thread.Start

Or all the new graphics stuff in System.Drawing.

Or having a vast number of new events for forms (like nearly all the ones that EventVB provided and some that it omitted)

Or having direct access to the WndProc for any messages you create (no more subclassing as it was)

Or serialization/deserialization of compound classes to-from XML.

[Wokawidget]

Interesting...Hmmmmmmm.
But you still can't have icons in menus Booooooooooo

Woka

[Wokawidget]

Oh, and MDI forms still suck

Woka

[Frans C]

Originally posted by Wokawidget
Interesting...Hmmmmmmm.
But you still can't have icons in menus Booooooooooo

Woka

It isn't realy that hard to make an ownerdrawn menu in .NET, so you can put in the menu whatever you like.

[Edneeis]

Don't forget about inheritance and reflection, two of my favs. Oh and delegates can come in handy once in a while.

[Wokawidget]

G'm-buh?

Woka

[Edneeis]

Originally posted by Wokawidget
G'm-buh?

Woka

Is that in reference to the MDI Forms, the Icon Menus, or my post?

Inheritance I'm sure you've probably heard about. Reflection is finding out information about your objects at runtime, like what the variable name is or what type of object it is. A few cool things about this is Enums can be transferred back and forth between their numeric value and the string name. It can actually do a ton more than that but that was the first thing I thought was cool. Delegates are like function pointers or a variable that holds a function instead of a value.

[Wokawidget]

• G'mbuh?
• m'buh?
• m-b?
• fl-m?
• j g-m-fl'buh?

Are all the same, they translate to "What? Please explain kind Sir."



Are you trying to scare me away from .NET?! Grrrrrrrrrrrrrrrr

Woka

[Edneeis]

There is nothing to fear except fear itself
...and some large animals
...and a women on her period
...and maybe a badger with young'ins
...or what about a few people we all know
...and sometimes clowns can be scary
...well anyway there may be things to fear but .NET isn't one of them.

Its just like most things in the industry and sounds more complicted than it is.