Is Form being Loaded as a SubForm

[MarkK]

Colin, I will take a look.

 

[isladogs]

Excellent - just what I was hoping....

BTW that example is a relatively simple one.

At the other extreme, I have a highly complex form used for multiple purposes with around 500 controls.
It has around 20-25 groups of tagged controls which are made hidden/visible; locked/unlocked; enabled/disabled; highlighted or not ... all using tags.

Just so you know what I'll propose next ...

 

[MarkK]

Tony, one thing you can do here,

   If Ctrl.Form.Hwnd = oForm.Hwnd Then
      blnIsA_Sub = True
   End If

...although it looks like Hwnd is working, is use "Is", like...

   If Ctrl.Form Is oForm Then
      blnIsA_Sub = True
   End If

...which, of course, can be further reduced to...

   blnIsA_Sub = Ctrl.Form Is oForm

Is compares instances, not types, so it is only true if the two operands point to the same instance of the object.

I do not get an error running your code from the load event of a subform.

Also, given how much effort this code goes thru to determine if the object is a subform, therefore I would rather do this test, event though it means intentionally raising an error...

Property Get MeIsASubform As Boolean
   On Error Resume Next
   MeIsASubform = Left(Typename(Me.Parent), 4) = "Form"
End Property

...and it also always makes more sense to me for an object to expose it's own properties that to hand the object over to an external routine to run a test on it from the outside. For encapsulation, I want that test to run INSIDE the object, and for the result to be exposed as a property or method.
Does this address the topic you raise, or have I missed the point?
Mark

 

[MarkK]

Colin, I was going to say "no, I won't do it," because what starts to cloud the issue is the infrastructure or maybe the "meta-structure" required to demonstrate the issue.

At its simplest, here's what we are talking about: We might need to selectively enable or disable four buttons until all data is entered in a form, say. At that level, I can

• .Tag those four buttons and run a big loop thru all controls, test for .Tag, and set the state, or I can
• expose a four member array I pre-populated with said buttons, enumerate that array, and set the state.

Two simple choices for how to make that work.

But looking at your form, there are groups, and mixed groups, and labels that belong to other controls, and so on, and so suddenly there is the bigger problem, like a meta-problem, of managing all the different groups that get hidden while the other group gets disabled. And once all that overhead is taken into account, will the simple two point description, above, be significantly improved? Probably not. You still either gonna .Tag them, or put 'em in an array.

But as to your last post, if I wrote a demo like the one you did, I would write a class, maybe called cControlGroup, that has properties like .Visible and .Enabled. Also, there would be a .Load method that takes a ParamArray which would be the list of controls, untagged, that belong to that group. Maybe this goes to what you are talking about with your 500 control form.

Imagine a cControlGroup class that could be used like this...

Private m_ccgA as cControlGroup
Private m_ccgB as cControlGroup

Property Get GroupA As cControlGroup
   If m_ccgA Is Nothing then 
      Set m_ccgA = New cControlGroup
      m_ccgA.Load [COLOR="Blue"]Me.Text0, Me.Text2, Me.Text[/COLOR]
   End If
   Set GroupA = m_ccgA
End Property

Property Get GroupB As cControlGroup
   If m_ccgB Is Nothing then 
      Set m_ccgB = New cControlGroup
      m_ccgB.Load [COLOR="blue"]Me.cmd1, Me.cmd2, Me.cmd3[/COLOR]
   End If
   Set GroupB = m_ccgB
End Property

Private Sub Text0_AfterUpdate()
   Me.GroupB.Enabled = Me.GroupA.HasNoNullValue
End Sub

So if we write a class that manages a set of controls, and that set of controls is defined by simply passing them into that class in the constructor, that makes a lot of sense to me. See what's going on in that code? Constructors, essentially, for classes that manage groups of controls, and then the form's code just leverages those classes.

That's how I'd approach that problem. But I'm not going to because I don't have time right now, but I would comment on it, as I'm doing, like this, in this post...

Hope this helps, makes sense, etc...
Cheers,
Mark

 

[isladogs]

Hi Mark

Yes that makes sense ... I think but I'd need to try it to be sure I understand properly.
Unfortunately, I don't have the time right now either!

I don't blame you in the least for not spending the time on the challenge
If you had asked me to do the same in reverse, I would probably have declined as well!

Just to give you an idea of the multi-purpose form I mentioned, attached are 4 randomly selected views showing a few of its many different uses.
Also attached is the same form in design view though most of the controls are hidden under other controls ....

Its taken many years to reach this level of complexity & it works well.
The main advantage is being able to reuse the same code repeatedly
BUT whether I'd do it again like this if I started again now is another matter...

 

[Uncle Gizmo]

BUT whether I'd do it again like this if I started again now is another matter...

That's the ultimate question!

The answer is 42....



Sent from my SM-G925F using Tapatalk

 

[isladogs]

That's the ultimate question!
The answer is 42....

LOL

Apologies to the OP - this thread has moved away from the original question onto a much wider discussion
In fact following Tony's reply, possibly the most fundamental question of all

I remember using Douglas Adams famous answer to

"what's the meaning of life, the universe and everything?"

as a personal reference to re-check some rarely used & obscure code which in my view was a bit of a muddle i.e.

at sixes and sevens

Hopefully the connection is obvious...

NOTE: for non English residents, Wikipedia lists the phrase as

"At sixes and sevens" is an English idiom used to describe a condition of confusion or disarray.

Anyway, as it was obscure, I promptly forgot about the code until about a year later a client demanded to know why the app gave had a message box saying 42 when he performed a particular action ....

Needless to say they'd never heard of Douglas Adams so it was a bit hard to explain

Anyway, the real answer is that I not only would, but do, continue to create multi-purpose forms.
However, none so far have reached the same degree of complexity as the one I described

 

[Uncle Gizmo]

I do not get an error running your code from the load event of a subform.

Hi Mark,
I have Incorporated your suggested update to the code thank you!

You said it worked for you, which puzzled me because it threw an error when I used it. I wondered what could be the difference between our two set-ups.

It occurred to me you would probably try it on a main form with a single subform, I’m using a main form with two subforms. I did an experiment with a main form and single subform and sure enough it worked!

That hints at the cause of the error. The code is checking all of the subform/subreport controls. It must be finding one which has yet to load. I'm readdressing the code to see if I can get it to only look at itself so to speak. If/when I get it working without error, I will repost it!

 

[mloucel]

I wouldn’t do it in each instance of the subform, I’d do it from the Main Form….

Also, I'm uncomfortable when an Error is triggered deliberately to make something happen. However, it can't be avoided all of the time and is sometimes a necessary evil.

In this particular case I can see a way which would avoid such an abuse of MS Access!

I would look at the problem from a different perspective.

There's no such thing as a “Sub-Form”! What you have on your “Main Form” is an ordinary form housed within a subform/subreport control, which I refer to as a subform window. The term “Subform” is a useful way of explaining what you see, however the term does tend to take your eye off the ball so to speak, because the form (Subform) isn’t actually on the Main Form it actually resides within the subform/subreport control.

There is a natural tendency to think about Controls, Forms, Objects as individual entities, however most things in MS Access are members of a collection. There's no exception in this case, your command button is one of the controls in the controls collection of the form it’s on. The form itself is housed within the subform window. It’s not necessary to refer to this form by its full name, you just refer to it as an object, as the object contained within that subform window a “Form”

Once you think about writing your code to take advantage of these Collections of Controls, then there are loads of fascinating and interesting things you can do. In this case, I would approach the problem from the “Main Form” perspective, not the subform perspective.

I would write code in the main form that would traverse the Main Form’s Controls Collection when the main form loads.

in your main form's “Load Event” (the form housing all of the identical subforms), run the code below. The code will seek out all of your subforms it will look in each form and see if it has a command button named “btnToHide” and set it's visible property to false...

Private Sub Form_Load()
Dim Ctrl As Control

    For Each Ctrl In Me.Controls
   
        Select Case Ctrl.ControlType
            Case acSubform
                Ctrl.Form.btnToHide.Visible = False
       
        End Select
   
    Next Ctrl

End Sub      'Form_Load

Thanks, this is OLD, but I found my solution, I just tweak it a bit.
I wanted to avoid a control "SubForm" to open if the superadmin is login [me], so that I can perform a Compact and Repair thru VBA, I ask the question here in the forums, but I had no luck:

https://www.access-programmers.co.uk/forums/threads/open-a-form-with-a-sub-form.332459/#post-1939406

so, I started lurking around and I found your code, I modify it, possibly not the best solution, but surely works for me [SO FAR].

So, this is the final code, if you have any suggestions, it will be appreciated.

' 
Private Sub Form_Load()
Code by @Uncle Gizmo [AWF]
' https://www.access-programmers.co.uk/forums/threads/is-form-being-loaded-as-a-subform.297204/
'

Dim Ctrl As Control
For Each Ctrl In Me.Controls

    Select Case Ctrl.ControlType
        Case acSubform
            'Ctrl.Form.btnToHide.Visible = False
            ' Stops the Subform from Loading ?
            Me.AuthorizationsView.Enabled = False
            Me.AuthorizationsView.SourceObject = "AuthFullViewDummyF"
            
            
    End Select

Next Ctrl
End Sub

Thanks

Maurice.

 

[Uncle Gizmo]

Hi Morris,

Great code! I made a small tweak by wrapping the Me.AuthorizationsView lines in a With statement for a bit of extra clarity and efficiency. It’s not essential here, but useful if more properties get added in the future.

Private Sub Form_Load()
    'Code by @Uncle Gizmo [AWF]
    'https://www.access-programmers.co.uk/forums/threads/is-form-being-loaded-as-a-subform.297204/
    
    Dim Ctrl As Control
    For Each Ctrl In Me.Controls
    
        Select Case Ctrl.ControlType
            Case acSubform
                ' Example code where we're using a With statement
                With Me.AuthorizationsView
                    .Enabled = False
                    .SourceObject = "AuthFullViewDummyF"
                End With
                
        End Select
        
    Next Ctrl
End Sub

 

[mloucel]

Hi Morris,

Great code! I made a small tweak by wrapping the Me.AuthorizationsView lines in a With statement for a bit of extra clarity and efficiency. It’s not essential here, but useful if more properties get added in the future.

Private Sub Form_Load()
    'Code by @Uncle Gizmo [AWF]
    'https://www.access-programmers.co.uk/forums/threads/is-form-being-loaded-as-a-subform.297204/
   
    Dim Ctrl As Control
    For Each Ctrl In Me.Controls
   
        Select Case Ctrl.ControlType
            Case acSubform
                ' Example code where we're using a With statement
                With Me.AuthorizationsView
                    .Enabled = False
                    .SourceObject = "AuthFullViewDummyF"
                End With
               
        End Select
       
    Next Ctrl
End Sub

Thank you, sir, I am working in a small option, if it works, I will post it.