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Object Variable Declaration

If I declare and instanciate a specific object variable (using early binding) in the general declaration area of a form, when is that object created?

Assuming the type of project is an Active X Document (if that makes any difference).

ie

Dim objie as New InernetExplorer

Is it when the application is first openned? When before or after form is first initialised?
When Internet Explorer is first openned?
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Lisp
Asked:
Lisp
1 Solution
 
msterjevCommented:
When the form is initialized(loaded into the memory - before Form_Load)
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LispAuthor Commented:
Do you mean before the initialise event is fired or after?
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msterjevCommented:
Before
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LispAuthor Commented:
According to the MCSD 70-176 practice exam from UCertify it occurs when the object is first used.

This makes no sense to me.  Another question they had related to the CDROM AutoRun feature and it said you had to change the name of your setup.exe file to autorun.exe.  There is a reference to this in MSDN but I think it is some ancient way of doing it.  Apparently that's how it was done on the windows 95 CD.


Can anybody please verfy this?

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VKCommented:
Hello Lisp !

You can find it out by yourself by setting a breakpoint in the Class_initialize event.

V.K.
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mdouganCommented:
I just ran a test (as VK suggested) and sure enough, an object variable declared in the General Declarations Section of a form as:

Dim oProfile As New cProfile

Won't actually be instantiated until the first time it is referenced.  So, in my code, my Form_Load procedure called another sub to load a combo box, and that sub procedure referenced the object and that is when the initialize event of the object fired.
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PaulHewsCommented:
Yes it is counter intuitive, but that's how it works.  Best practice is to explicitly create your object in your code rather than use the above method of implicit instantiation.  In other words, use

Dim o as clsMyObj
Set o = New clsMyObj

instead of:

Dim o as New clsMyObj

There are a few good reasons to do this.  One is that referring to an uninstantiated variable NOT declared with New will raise an error, allowing you to see clearly where you are using said object.  Declaring with new makes it hard to know that an object has been released, as any reference to it will not return an error and testing If o Is Nothing will never return true.
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Richie_SimonettiIT OperationsCommented:
I agree with Paul, besides....

Dim objie as New InernetExplorer

sub test()
objie.visible=true ' or whatever: here is created a shown
end sub
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rspahitzCommented:
All this actually makes sense for the same reason that dlls work the way they do--only use what you need.

If you have two forms, and never load the second, does it make sense for your project to load it?  Of course not.

However, if you have two forms and the second one takes a long time to load, you have the choice of when to load it--either when the user needs if, or when the application begins (via code.)

--
When does an object get loaded?  I would say (based on experience with user controls) that it works as follows:

(Event) Initialize container
1.identify all pieces of memory associated with the container/form (essentially variables)
2.fire initializeproperty event

Initialize Property
1.load all controls/objects
2.load all persistent data for these controls from a property bag
3.fire load event

Load
1.gather information about object properties, methods and events
2.if needed, fire the show/paint event

Show
1.set object properties to visible and enabled (if not told otherwise
2.paint the control's appearance into the correct location
3.fire activate event

Activate
1.set the window to be the primary window, and to receive events by default
2.wait for user interaction or other events

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LispAuthor Commented:
Thanks.  This was confusing the hell out of me.
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