Re: UserControl and CreateObject
emailstartsafterthisunderscore_russnewcomer_andendsafterthatone_at_gmail.com
Date: 12/30/04
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Date: 30 Dec 2004 07:45:08 -0800
russnewcomer@gmail.com wrote:
> Greetings, group. I have been lurking for ~8 months now, and have
> gotten a lot of valuable help from reading and searching the
archives.
> I have now come upon a problem that I cannot find described anywhere
> else, and am wondering if anyone has any pointers that could help me.
>
> I have a UserControl that encapsulates a MSCOMM object. It takes the
> raw data from a Bluetooth-based barcode scanner that is aliased to a
> COM port, validates the data, and then returns the information to a
> form. This control is being used in an MDI project. So I can avoid
> opening and closing the COM port throughout the project, I have been
> using a globably defined variable (Public g_scanCtl as Object) to
hold
> the instance of the UserControl.
>
> I have been using the line
>
> Set g_scanCtl = CreateObject("LaserFab.Scanner")
>
> inside Sub Main() to create an instance of the object. I was unable
to
> use the New keyword because I do not have any instance of the
> UserControl on any of my forms inside the project.
>
> Now, here is the kicker : I was doing some testing earlier today to
> test situations where a computer does not have the Bluetooth scanner
> connected, and commented out the Set g_scanCtl... line above. I
> compiled a version, ran it on a test machine. After finishing my
> testing, I removed the comment, and upon the next run of the project,
I
> was greeted with :
>
> Run-Time error '429':
>
> ActiveX Component Can't create object.
>
>
> This error did not appear before I commented, compiled, and removed
the
> comment above.
>
> Now, I was able to work around the problem by using the following
line
> (That I consider sub-optimal) in the stead of the CreateObject()
call:
>
> Set g_scanCtl = frmMain.Controls.Add("LaserFab.Scanner", "scn")
>
> I also changed the declaration of g_scanCtl to Object instead of
> Control, although I believe this change was probably superfluous to
the
> process, since it works either way.
>
> But my question is, what did I do that caused this problem? (Can't
> create Object) Did I somehow unregister my UserControl (which is part
> of the LaserFab project)?
>
> I consider my work-around suboptimal because I only want to create a
> Scanner control if the user has a scanner attached to their machine,
> and I was not keen on directly placing the control on my App, even
> dynamically. Does this matter?
>
> Thanks in advance for any help you may be able to provide.
>
>
> Russ Newcomer
>
emailstartsafterthisunderscore_russnewcomer_andendsafterthatone@gmail.com
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