Hello to all!
Does any of you want to comment the approach I implement for
instantiating a form? A description and an example follow.
Cheers,
RV
jmclopesAThotma il.com replace the AT with the thing you know ;-)
After discovering that access 2000 support form properties (I'm a
newbie, alright :-) ), I was pleased with the idea of organizing my
code with some object oriented approach. Something like:
- instantiate a form
- set form properties
- display the form
- read form properties
- do whatever required
Then I realized (at least I didn't find how) that I couldn't open the
form in a way that the procedure execution would stop until the form
is closed. With the following code, the form is displayed but the
procedure continues its execution and, when it ends, the form is
destroyed:
Sub my_proc()
Dim f As New Form_my_form
f.Message = "Hello form!" ' Message it's a property I added to
the form
'The user would enter some text in a textbox,
'which the form returns with the property Message
f.visible=true
MsgBox f.Message
Set f = Nothing
End Sub
So I solved this problem as follows. The idea is after the form is
displayed, the procedure loops while the form is visible. The form is
made not visible when the user presses the OK in that form.
'-------- NEW VERSION of my_proc() -----------
Sub my_proc()
Dim f As New Form_my_form
f.Message = "Hello form!" ' Message it's a property I added to
the form
'The user would enter some text in a textbox,
'which the form returns with the property Message
f.Modal = True ' one can set the form to modal to have a popup
behaviour
f.visible=true
While f.Visible
DoEvents
Wend
MsgBox f.Message
Set f = Nothing
End Sub
'-------- MY_FORM PROCEDURES -----------
Private Sub btnOk_Click()
Me.Visible = False
End Sub
Private Sub Form_Unload(Can cel As Integer)
'Don't unload the form, just hide it so the properties
'are still available to the caller
If Me.Visible Then
'only cancel the unload if the form isn't hidden
Me.Visible = False
Cancel = 1
End If
End Sub
19  3597 
I have seen few cases where it was useful to instantiate a form from code,
and those only when multiple copies of the same form were to be displayed
concurrently. The simple way is often best... and the simple way is to
design your form and set its properties in design view, then use
DoCmd.OpenForm to open the single copy that is usually all that is needed.
Access is not your typical programming language that is code intensive, and
that is one of its very strong points.
If there's followup to this thread, I hope someone can pick it up, because I
am going to be out of the newsgroups for several days.
Larry Linson
Microsoft Access MVP
"Raposa Velha" <jm******@hotma il.com> wrote in message
news:69******** *************** ***@posting.goo gle.com... Hello to all!
Does any of you want to comment the approach I implement for
instantiating a form? A description and an example follow.
Cheers,
RV
jmclopesAThotma il.com replace the AT with the thing you know ;-)
After discovering that access 2000 support form properties (I'm a
newbie, alright :-) ), I was pleased with the idea of organizing my
code with some object oriented approach. Something like:
- instantiate a form
- set form properties
- display the form
- read form properties
- do whatever required
Then I realized (at least I didn't find how) that I couldn't open the
form in a way that the procedure execution would stop until the form
is closed. With the following code, the form is displayed but the
procedure continues its execution and, when it ends, the form is
destroyed:
Sub my_proc()
Dim f As New Form_my_form
f.Message = "Hello form!" ' Message it's a property I added to
the form
'The user would enter some text in a textbox,
'which the form returns with the property Message
f.visible=true
MsgBox f.Message
Set f = Nothing
End Sub
So I solved this problem as follows. The idea is after the form is
displayed, the procedure loops while the form is visible. The form is
made not visible when the user presses the OK in that form.
'-------- NEW VERSION of my_proc() -----------
Sub my_proc()
Dim f As New Form_my_form
f.Message = "Hello form!" ' Message it's a property I added to
the form
'The user would enter some text in a textbox,
'which the form returns with the property Message
f.Modal = True ' one can set the form to modal to have a popup
behaviour
f.visible=true
While f.Visible
DoEvents
Wend
MsgBox f.Message
Set f = Nothing
End Sub
'-------- MY_FORM PROCEDURES -----------
Private Sub btnOk_Click()
Me.Visible = False
End Sub
Private Sub Form_Unload(Can cel As Integer)
'Don't unload the form, just hide it so the properties
'are still available to the caller
If Me.Visible Then
'only cancel the unload if the form isn't hidden
Me.Visible = False
Cancel = 1
End If
End Sub
Raposa Velha wrote: Hello to all!
Does any of you want to comment the approach I implement for
instantiating a form? A description and an example follow.
Yes.
What's the point?
You have discovered one of the many limitations of the technique of
instantiating forms using the New keyword. In general, you can find another
way to do the same thing, and avoid the problem.
In the rare cases when the techniquer really does add enough value to
compensate for the added complexity and instability (e.g. the form will close
if the code gets reset), at least make sure you write your code in an
event-driven manner so that you don't need your code to halt and wait for the
form to close. Instead, use events on the form to trigger the follow-up
action.
Note that you can bootstrap a form reference by having the form reference
itself, so it doesn't close when the procedure that opens it exits (the
alternative is some sort of messy open instances collection). Just make sure
the form sets its self-reference to Nothing on Form_Close, so all resources
are freed up.
On 28 Dec 2004 10:52:56 -0800, jm******@hotmai l.com (Raposa Velha) wrote: Hello to all!
Does any of you want to comment the approach I implement for
instantiatin g a form? A description and an example follow.
Cheers,
RV
jmclopesAThotm ail.com replace the AT with the thing you know ;-)
After discovering that access 2000 support form properties (I'm a
newbie, alright :-) ), I was pleased with the idea of organizing my
code with some object oriented approach. Something like:
- instantiate a form
- set form properties
- display the form
- read form properties
- do whatever required
Then I realized (at least I didn't find how) that I couldn't open the
form in a way that the procedure execution would stop until the form
is closed. With the following code, the form is displayed but the
procedure continues its execution and, when it ends, the form is
destroyed:
Sub my_proc()
Dim f As New Form_my_form
f.Message = "Hello form!" ' Message it's a property I added to
the form
'The user would enter some text in a textbox,
'which the form returns with the property Message
f.visible=true
MsgBox f.Message
Set f = Nothing
End Sub
So I solved this problem as follows. The idea is after the form is
displayed, the procedure loops while the form is visible. The form is
made not visible when the user presses the OK in that form.
'-------- NEW VERSION of my_proc() -----------
Sub my_proc()
Dim f As New Form_my_form
f.Message = "Hello form!" ' Message it's a property I added to
the form
'The user would enter some text in a textbox,
'which the form returns with the property Message
f.Modal = True ' one can set the form to modal to have a popup
behaviour
f.visible=true
While f.Visible
DoEvents
Wend
MsgBox f.Message
Set f = Nothing
End Sub
'-------- MY_FORM PROCEDURES -----------
Private Sub btnOk_Click()
Me.Visible = False
End Sub
Private Sub Form_Unload(Can cel As Integer)
'Don't unload the form, just hide it so the properties
'are still available to the caller
If Me.Visible Then
'only cancel the unload if the form isn't hidden
Me.Visible = False
Cancel = 1
End If
End Sub
Thanks Larry.
I see your point about keeping it simple. The main idea of this approach is
having a reusable form that would read some global variables and set some
other global variables. This is the alternative I can image for comunication
among different parts of the application with this generic form. This way,
it requires both the form and the rest of the application to be aware of
these global variables. On the other hand, the use of properties would
overcome the use of global variables.
RV
"Larry Linson" <bo*****@localh ost.not> wrote in message
news:xpnAd.1183 6$tG3.85@trnddc 02... I have seen few cases where it was useful to instantiate a form from code,
and those only when multiple copies of the same form were to be displayed
concurrently. The simple way is often best... and the simple way is to
design your form and set its properties in design view, then use
DoCmd.OpenForm to open the single copy that is usually all that is needed.
Access is not your typical programming language that is code intensive,
and
that is one of its very strong points.
If there's followup to this thread, I hope someone can pick it up, because
I
am going to be out of the newsgroups for several days.
Larry Linson
Microsoft Access MVP
"Raposa Velha" <jm******@hotma il.com> wrote in message
news:69******** *************** ***@posting.goo gle.com... Hello to all!
Does any of you want to comment the approach I implement for
instantiating a form? A description and an example follow.
Cheers,
RV
jmclopesAThotma il.com replace the AT with the thing you know ;-)
After discovering that access 2000 support form properties (I'm a
newbie, alright :-) ), I was pleased with the idea of organizing my
code with some object oriented approach. Something like:
- instantiate a form
- set form properties
- display the form
- read form properties
- do whatever required
Then I realized (at least I didn't find how) that I couldn't open the
form in a way that the procedure execution would stop until the form
is closed. With the following code, the form is displayed but the
procedure continues its execution and, when it ends, the form is
destroyed:
Sub my_proc()
Dim f As New Form_my_form
f.Message = "Hello form!" ' Message it's a property I added to
the form
'The user would enter some text in a textbox,
'which the form returns with the property Message
f.visible=true
MsgBox f.Message
Set f = Nothing
End Sub
So I solved this problem as follows. The idea is after the form is
displayed, the procedure loops while the form is visible. The form is
made not visible when the user presses the OK in that form.
'-------- NEW VERSION of my_proc() -----------
Sub my_proc()
Dim f As New Form_my_form
f.Message = "Hello form!" ' Message it's a property I added to
the form
'The user would enter some text in a textbox,
'which the form returns with the property Message
f.Modal = True ' one can set the form to modal to have a popup
behaviour
f.visible=true
While f.Visible
DoEvents
Wend
MsgBox f.Message
Set f = Nothing
End Sub
'-------- MY_FORM PROCEDURES -----------
Private Sub btnOk_Click()
Me.Visible = False
End Sub
Private Sub Form_Unload(Can cel As Integer)
'Don't unload the form, just hide it so the properties
'are still available to the caller
If Me.Visible Then
'only cancel the unload if the form isn't hidden
Me.Visible = False
Cancel = 1
End If
End Sub
The point of commenting ofr what to be commented? :-)
"rkc" <rk*@rochester. yabba.dabba.do. rr.bomb> wrote in message
news:3J******** ***********@twi ster.nyroc.rr.c om... Raposa Velha wrote: Hello to all!
Does any of you want to comment the approach I implement for
instantiating a form? A description and an example follow.
Yes.
What's the point?
Hi Steve.
Good tips, thanks!
The instability argument it's a strong one, strong enough to make me give up
of this approach. A pity, because this makes the application more similar to
a set of black boxes. Actually this idea come because I wanted to use the
properties capability. The thing is if I use the DoCmd.OpenForm to open the
form, can I still set the custom properties before opening the form? After
the user presses OK (for example), it's no problem reading the custom
properties: it's just a matter of hiding the form instead of closing it.
RV
"Steve Jorgensen" <no****@nospam. nospam> wrote in message
news:km******** *************** *********@4ax.c om... You have discovered one of the many limitations of the technique of
instantiating forms using the New keyword. In general, you can find
another
way to do the same thing, and avoid the problem.
In the rare cases when the techniquer really does add enough value to
compensate for the added complexity and instability (e.g. the form will
close
if the code gets reset), at least make sure you write your code in an
event-driven manner so that you don't need your code to halt and wait for
the
form to close. Instead, use events on the form to trigger the follow-up
action.
Note that you can bootstrap a form reference by having the form reference
itself, so it doesn't close when the procedure that opens it exits (the
alternative is some sort of messy open instances collection). Just make
sure
the form sets its self-reference to Nothing on Form_Close, so all
resources
are freed up.
On 28 Dec 2004 10:52:56 -0800, jm******@hotmai l.com (Raposa Velha) wrote:
Hello to all!
Does any of you want to comment the approach I implement for
instantiati ng a form? A description and an example follow.
Cheers,
RV
jmclopesAThot mail.com replace the AT with the thing you know ;-)
After discovering that access 2000 support form properties (I'm a
newbie, alright :-) ), I was pleased with the idea of organizing my
code with some object oriented approach. Something like:
- instantiate a form
- set form properties
- display the form
- read form properties
- do whatever required
Then I realized (at least I didn't find how) that I couldn't open the
form in a way that the procedure execution would stop until the form
is closed. With the following code, the form is displayed but the
procedure continues its execution and, when it ends, the form is
destroyed:
Sub my_proc()
Dim f As New Form_my_form
f.Message = "Hello form!" ' Message it's a property I added to
the form
'The user would enter some text in a textbox,
'which the form returns with the property Message
f.visible=true
MsgBox f.Message
Set f = Nothing
End Sub
So I solved this problem as follows. The idea is after the form is
displayed, the procedure loops while the form is visible. The form is
made not visible when the user presses the OK in that form.
'-------- NEW VERSION of my_proc() -----------
Sub my_proc()
Dim f As New Form_my_form
f.Message = "Hello form!" ' Message it's a property I added to
the form
'The user would enter some text in a textbox,
'which the form returns with the property Message
f.Modal = True ' one can set the form to modal to have a popup
behaviour
f.visible=true
While f.Visible
DoEvents
Wend
MsgBox f.Message
Set f = Nothing
End Sub
'-------- MY_FORM PROCEDURES -----------
Private Sub btnOk_Click()
Me.Visible = False
End Sub
Private Sub Form_Unload(Can cel As Integer)
'Don't unload the form, just hide it so the properties
'are still available to the caller
If Me.Visible Then
'only cancel the unload if the form isn't hidden
Me.Visible = False
Cancel = 1
End If
End Sub
Steve,
Can you elaborate on this 'bootstrap' concept? I currently use a
variation of the 'messy open instances collection' (I use a Public array
variable that gets ReDim'd for each new instance) and didn't know there
was an alternative.
Thanks.
--
Bri
Steve Jorgensen wrote: You have discovered one of the many limitations of the technique of
instantiating forms using the New keyword. In general, you can find another
way to do the same thing, and avoid the problem.
In the rare cases when the techniquer really does add enough value to
compensate for the added complexity and instability (e.g. the form will close
if the code gets reset), at least make sure you write your code in an
event-driven manner so that you don't need your code to halt and wait for the
form to close. Instead, use events on the form to trigger the follow-up
action.
Note that you can bootstrap a form reference by having the form reference
itself, so it doesn't close when the procedure that opens it exits (the
alternative is some sort of messy open instances collection). Just make sure
the form sets its self-reference to Nothing on Form_Close, so all resources
are freed up.
Raposa,
You can make a Form variable reference the form after you open it:
Air Code:
Dim frm as Form
DoCmd.Open acForm, "MyForm"
Set frm = Forms!MyForm
frm.Message= "Hello form!"
set frm = Nothing
This will not close the form when the frm is set to nothing. It will,
however, open the Form before applying the Property. This happens fast
enough that the user won't see the difference, but if there is code in
your OnOpen or OnLoad Events that depend on the Property, then those
events won't see it as it hasn't been set yet. An option to this is to
have the post Property code run in a Public Sub in the form, then you
could do this:
Air Code:
Dim frm as Form
DoCmd.Open acForm, "MyForm"
Set frm = Forms!MyForm
frm.Message= "Hello form!"
frm.MySub 'This is the Public Sub in the Form
set frm = Nothing
Hope that helps
--
Bri
Raposa Velha wrote: Hi Steve.
Good tips, thanks!
The instability argument it's a strong one, strong enough to make me give up
of this approach. A pity, because this makes the application more similar to
a set of black boxes. Actually this idea come because I wanted to use the
properties capability. The thing is if I use the DoCmd.OpenForm to open the
form, can I still set the custom properties before opening the form? After
the user presses OK (for example), it's no problem reading the custom
properties: it's just a matter of hiding the form instead of closing it.
RV
"Steve Jorgensen" <no****@nospam. nospam> wrote in message
news:km******** *************** *********@4ax.c om...
You have discovered one of the many limitations of the technique of
instantiati ng forms using the New keyword. In general, you can find
another
way to do the same thing, and avoid the problem.
In the rare cases when the techniquer really does add enough value to
compensate for the added complexity and instability (e.g. the form will
close
if the code gets reset), at least make sure you write your code in an
event-driven manner so that you don't need your code to halt and wait for
the
form to close. Instead, use events on the form to trigger the follow-up
action.
Note that you can bootstrap a form reference by having the form reference
itself, so it doesn't close when the procedure that opens it exits (the
alternative is some sort of messy open instances collection). Just make
sure
the form sets its self-reference to Nothing on Form_Close, so all
resources
are freed up.
On 28 Dec 2004 10:52:56 -0800, jm******@hotmai l.com (Raposa Velha) wrote:
Hello to all!
Does any of you want to comment the approach I implement for
instantiatin g a form? A description and an example follow.
Cheers,
RV
jmclopesATho tmail.com replace the AT with the thing you know ;-)
After discovering that access 2000 support form properties (I'm a
newbie, alright :-) ), I was pleased with the idea of organizing my
code with some object oriented approach. Something like:
- instantiate a form
- set form properties
- display the form
- read form properties
- do whatever required
Then I realized (at least I didn't find how) that I couldn't open the
form in a way that the procedure execution would stop until the form
is closed. With the following code, the form is displayed but the
procedure continues its execution and, when it ends, the form is
destroyed:
Sub my_proc()
Dim f As New Form_my_form
f.Message = "Hello form!" ' Message it's a property I added to
the form
'The user would enter some text in a textbox,
'which the form returns with the property Message
f.visible=true
MsgBox f.Message
Set f = Nothing
End Sub
So I solved this problem as follows. The idea is after the form is
displayed, the procedure loops while the form is visible. The form is
made not visible when the user presses the OK in that form.
'-------- NEW VERSION of my_proc() -----------
Sub my_proc()
Dim f As New Form_my_form
f.Message = "Hello form!" ' Message it's a property I added to
the form
'The user would enter some text in a textbox,
'which the form returns with the property Message
f.Modal = True ' one can set the form to modal to have a popup
behaviour
f.visible=true
While f.Visible
DoEvents
Wend
MsgBox f.Message
Set f = Nothing
End Sub
'-------- MY_FORM PROCEDURES -----------
Private Sub btnOk_Click()
Me.Visible = False
End Sub
Private Sub Form_Unload(Can cel As Integer)
'Don't unload the form, just hide it so the properties
'are still available to the caller
If Me.Visible Then
'only cancel the unload if the form isn't hidden
Me.Visible = False
Cancel = 1
End If
End Sub
Bri <no*@here.com > wrote in news:oxDAd.6023 27$Pl.99862@pd7 tw1no: Can you elaborate on this 'bootstrap' concept? I currently use a
variation of the 'messy open instances collection' (I use a Public
array variable that gets ReDim'd for each new instance) and didn't
know there was an alternative.
Have you considered a class module, which would automatically
re-initialize the stored values when it is re-instantiated?
--
David W. Fenton http://www.bway.net/~dfenton
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