I came across something by accident; assigning one object to another (as in
object1 = object2) allows me to "work on" object2 just like it was object1.
For instance, in order to be able to reference a textbox on form1 I created
a textbox at module level called PassTextBox and assigned the original
textbox to it (textbox1 = PassTextBox) in Form1's load code. I was planning
on just using this as a "hold" area and when I got back into Form1 I could
assign PassTextBox back to textbox1. But I found out that whatever I did to
PassTextBox (such as changing the .text property) WAS ALREADY DONE IN
textbox1! So this makes me think there's something inherent in the object
that I can't see (or am not aware of) that contains an address (pointer).
Are the two textboxes two separate entities that just "point" to the same
place? I see this could open up a lot of possibilities but also a lot of
potential problems. How do you make a true "copy" of an object (so that
changing a property in one doesn't affect the other)? It's almost like the
assign is working ByRef instead of ByVal.

--
Thanks,
Ricky W. Hunt
freendeed

you are ending up with 2 names for the same object
remember - object variables are reference types

to avoid this (if you need to)
create a different object and just copy the values into the new object -
being careful not to make the same mistake on member objects of the object
you're copying -
or - look up the clone method



"Ricky W. Hunt" <(E-Mail Removed)> wrote in message
news:wZbSc.282915$XM6.153027@attbi_s53...
> I came across something by accident; assigning one object to another (as
in
> object1 = object2) allows me to "work on" object2 just like it was
object1.
> For instance, in order to be able to reference a textbox on form1 I
created
> a textbox at module level called PassTextBox and assigned the original
> textbox to it (textbox1 = PassTextBox) in Form1's load code. I was
planning
> on just using this as a "hold" area and when I got back into Form1 I could
> assign PassTextBox back to textbox1. But I found out that whatever I did
to
> PassTextBox (such as changing the .text property) WAS ALREADY DONE IN
> textbox1! So this makes me think there's something inherent in the object
> that I can't see (or am not aware of) that contains an address (pointer).
> Are the two textboxes two separate entities that just "point" to the same
> place? I see this could open up a lot of possibilities but also a lot of
> potential problems. How do you make a true "copy" of an object (so that
> changing a property in one doesn't affect the other)? It's almost like the
> assign is working ByRef instead of ByVal.
>
> --
> Thanks,
> Ricky W. Hunt
> freendeed
>
>


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"Hal Rosser" <(E-Mail Removed)> wrote in message
news:%dhSc.4813$(E-Mail Removed)...
> you are ending up with 2 names for the same object
> remember - object variables are reference types

That's kind of what I had deduced. Thanks for claryfing. So if you had 100
such objects they'd really only take up the space of one?

>
> to avoid this (if you need to)
> create a different object and just copy the values into the new object -
> being careful not to make the same mistake on member objects of the object
> you're copying -
> or - look up the clone method

thanks.

"Ricky W. Hunt" <(E-Mail Removed)> wrote in message
news:bTiSc.284516$Oq2.99946@attbi_s52...
> That's kind of what I had deduced. Thanks for claryfing. So if you had 100
> such objects they'd really only take up the space of one?
>

Yep. Technically, the space of one and the space of [up to] 100 pointers to
it. In general, "reference type" means "variable is only a pointer". A
side effect of this is that ByRef and ByVal are pretty much the same for
objects and/or reference types. ByVal will still make a copy, as you would
expect, but it is only copying the pointer, not the entire object.

Some more explanation:

http://msdn.microsoft.com/library/de...gmechanism.asp

Best Regards,

Andy

"Andy Becker" <(E-Mail Removed)> wrote in message
news:%(E-Mail Removed)...
> "Ricky W. Hunt" <(E-Mail Removed)> wrote in message
> news:bTiSc.284516$Oq2.99946@attbi_s52...
> > That's kind of what I had deduced. Thanks for claryfing. So if you had
100
> > such objects they'd really only take up the space of one?
> >
>
> Yep. Technically, the space of one and the space of [up to] 100 pointers
to
> it. In general, "reference type" means "variable is only a pointer". A
> side effect of this is that ByRef and ByVal are pretty much the same for
> objects and/or reference types. ByVal will still make a copy, as you
would
> expect, but it is only copying the pointer, not the entire object.

Wow. This is kind of shocking but good to know.