Detecting if scrollbar is currently displayed

[EonsTimE]

Hi,


I'm using the following code to detect whether a scrollbar (horizontal/vertical) is displayed in Access form/control:

Option Compare Database
Option Explicit


Private Const GWL_STYLE = (-16)
Private Const WS_HSCROLL = &H100000
Private Const WS_VSCROLL = &H200000


Private Declare Function GetWindowLong Lib "user32" Alias "GetWindowLongA" (ByVal Hwnd As Long, ByVal nIndex As Long) As Long

Public Function IsHScrollVisible(Hwnd As Long) As Boolean
    Dim Style As Long
    Style = GetWindowLong(Hwnd, GWL_STYLE)
 
    If (Style And WS_HSCROLL) Then
        IsHScrollVisible = True
        Exit Function
    End If
 
End Function
 


Public Function IsVScrollVisible(Hwnd As Long) As Boolean
    Dim Style As Long
    Style = GetWindowLong(Hwnd, GWL_STYLE)
 
    If (Style And WS_VSCROLL) Then
        IsVScrollVisible = True
        Exit Function
    End If
 
End Function

Then, I'm calling the functions on a form with a button:

Private Sub Command1_Click()


MsgBox IsVScrollVisible(Me.Hwnd)
MsgBox IsHScrollVisible(Me.Hwnd)
'MsgBox IsVScrollVisible(Forms!Form1.Hwnd) 'Direct pointer doesn't work either
'MsgBox IsHScrollVisible(Forms!Form1.Hwnd) '

End Sub

Problem is, the result is always 'False', even if I shrink the form to display a scrollbar.
I would appreciate an insight as to any errors in my approach, thank you.

[Micron]

I see you are using Access 2016 (uses 64 bit handlers and pointers) but the code is written for 32 bit. Just a guess, but maybe your issue is that you should be using GetWindowLongPtr.

[EonsTimE]

I see you are using Access 2016 (uses 64 bit handlers and pointers) but the code is written for 32 bit. Just a guess, but maybe your issue is that you should be using GetWindowLongPtr.

Hmm, I'm writing on the assumption the code should run on 32bit machines.
Wouldn't declaring 32bit DLL and pointers be not enough to assure 32bit execution? I'm running Access in 32bit too, but on Win10 x64. I'd rather not switch to 64bit; that would raise unnecessary compatibility issues when I reuse the code.

Stepping through the functions, looks like the code is resolving just fine. Maybe constant declarations are wrong pointers?

Private Const WS_HSCROLL = &H100000
Private Const WS_VSCROLL = &H200000

My makeshift form looks like this:

[orange]

Just curious--- why do you need to do this in code? I'm sure there is an explanation, but this is not a common need.

[EonsTimE]

Just curious--- why do you need to do this in code? I'm sure there is an explanation, but this is not a common need.

Well, I'm probably OCD... Basically, for quite a few things I want to do in Access I will have some subforms on a main form. And when I populate those sub forms with controls, let's say text boxes, I want to resize them so that a vertical scrollbar doesn't cover their contents. I know, you'll say "just asume the scrollbar is always there", but my OCD...
And second purpose is, in general, I have a code that resizes/rearranges controls (especially subform containers) on a main form as you resize the main form, or when you make the main form DoCmd.Maximize
If this code worked, it'd let me use every inch of space on the form more effectively. Sorry for bein pain...

NB, I've tried the code in Access2010 and it too gives always False as answer to the presence of scrollbars.

The code from the first post is self contained, just put it in a module, assign a call to a Command1 button and step through. Maybe you'll see something I don't

[EonsTimE]

I guess my issue is with 32/64 value conversions. Tried to rewrite the code with PtrSafe versions of Long etc, but no luck yet.

So far it looks more like this

Option Compare Database
Option Explicit

Public Const GWL_STYLE = (-16)
Public Const WS_HSCROLL = &H100000
Public Const WS_VSCROLL = &H200000


'Private Declare Function GetWindowLong Lib "user32" Alias "GetWindowLongA" (ByVal Hwnd As Long, ByVal nIndex As Long) As Long ' original version
Private Declare PtrSafe Function GetWindowLong Lib "user32" Alias "GetWindowLongA" (ByVal hwnd As LongPtr, ByVal nIndex As LongPtr) As LongPtr  ' no dice


Public Function IsHScrollVisible(hwnd As Long) As Boolean
    Dim Style As LongPtr
    Style = GetWindowLong(hwnd, GWL_STYLE)  ' stepping here I get something like 3994356 and -16 for hwnd and GWL_Style
 
    If (Style And WS_HSCROLL) Then  ' stepping here I ver numbers like -1753456456 and 10453345 for Style and WS_HSCROLL
        IsHScrollVisible = True
        Exit Function
    End If
 
End Function
 

Public Function IsVScrollVisible(hwnd As Long) As Boolean
    Dim Style As LongPtr
    Style = GetWindowLong(hwnd, GWL_STYLE)
 
    If (Style And WS_VSCROLL) Then
        IsVScrollVisible = True
        Exit Function
    End If
 
End Function

This was some interesting read
http://www.utteraccess.com/forum/ind...post&p=1914378

[orange]

Very interesting dialog indeed.
Since you are interested in forms and making full use of available space, you may find this article of interest.
I found it accidentally just recently.

[Micron]

I tried your code with the same results. Only if I reduced the value of the scroll value could I ever get either of the two comparisons (e.g. (Style And WS_VSCROLL)) to be true. This type of comparison AFAIK, is a bit-wise compare, which I don't see how it could (almost) ever be true, but I'm no expert on that. Since IsHScrollVisible and IsVScrollVisible appear to be methods of an Access form (check intellisense), I also suspect an issue with having a function with the same name as a method. In fact, I created a continuous loop in my attempts to figure it out (luckily I was always in break mode). I also see that most of the examples related to your code are based in C+ or vb.net - so there may not be a direct application of your posted code when using Access. However, this seems to work:

Dim bytBars As Byte

bytBars = Me.Form.ScrollBars

  If bytBars = 0 Then
   MsgBox "There are currently no scrollbars detected."
    Else
   MsgBox "There is at least one scrollbar detected."
  End If

Wish I could take credit for the code, especially if it works for you as it did for me, but I found it here:
http://www.tek-tips.com/viewthread.cfm?qid=1258350

[orange]

See if this helps https://msdn.microsoft.com/en-us/lib...ice.14%29.aspx I adjusted my TestMessage form as per the attached jpg.

then in immediate window (form was open)
?forms("TestMessage").ScrollBars
1

The 1, as per the info in link above, indicates Horizontal scroll bar.

My jpg shows form in Design view. I also tried this in Form view and it still returns 1.

Good luck.

[EonsTimE]

Very interesting dialog indeed.
Since you are interested in forms and making full use of available space, you may find this article of interest.
I found it accidentally just recently.

Thank you Orange, and I'll return the favour by giving something I've found recently myself.
The code is neat and not too hard to follow.
http://www.databasejournal.com/featu...ike-Access.htm
Main features you might enjoy looking at:
- resizes 4 subforms to fill in the whole of the main form, resizes subform content too
- Back and Forward buttons, webbrowser style
- records presented as heperlink-fakes
- neat solution at displaying each form's title and description (check out lblCaption, lblDescription and imgLogo formatting)

[EonsTimE]

I tried your code with the same results. Only if I reduced the value of the scroll value could I ever get either of the two comparisons (e.g. (Style And WS_VSCROLL)) to be true. This type of comparison AFAIK, is a bit-wise compare, which I don't see how it could (almost) ever be true, but I'm no expert on that. Since IsHScrollVisible and IsVScrollVisible appear to be methods of an Access form (check intellisense), I also suspect an issue with having a function with the same name as a method. In fact, I created a continuous loop in my attempts to figure it out (luckily I was always in break mode). I also see that most of the examples related to your code are based in C+ or vb.net - so there may not be a direct application of your posted code when using Access. However, this seems to work:

Dim bytBars As Byte

bytBars = Me.Form.ScrollBars

  If bytBars = 0 Then
   MsgBox "There are currently no scrollbars detected."
    Else
   MsgBox "There is at least one scrollbar detected."
  End If

Wish I could take credit for the code, especially if it works for you as it did for me, but I found it here:
http://www.tek-tips.com/viewthread.cfm?qid=1258350

Thanks Micron, I'll play with your code tomorrow (zzz). I'm just beginning to go seriously at programming albeit been script kiddie for years, so please bear with my incompetence

My api code was based on example showcased on Microsoft's page
https://support.microsoft.com/en-us/kb/299686
I guess Microsoft were convinced it would work, or maybe I've implemented it sloppily trying to port VB.

[EonsTimE]

See if this helps https://msdn.microsoft.com/en-us/lib...ice.14%29.aspx I adjusted my TestMessage form as per the attached jpg.

then in immediate window (form was open)
?forms("TestMessage").ScrollBars
1

The 1, as per the info in link above, indicates Horizontal scroll bar.

My jpg shows form in Design view. I also tried this in Form view and it still returns 1.

Good luck.

Thanks, I'm aware of that property, but I've just realised that I haven't checked if the result of ?forms("TestMessage").ScrollBars would show 0 if the scrollbar is not needed and not displayed ("Hey, at the moment I'm not displaying a scrollbar, but not gonna tell you whether I'm allowed to display one of need be"). My assumption was, it would always show 1 ("I'm capable of displaying a scrollbar, but not gonna tell you whether I'm displaying one right now or not") if the setting is as shown in your Property Sheet screenshot. That's something to play with tomorrow.

[Micron]

I checked your link. VB / VBA often inter-compatible, but not always.
Also of interest is that the page shows this comparison (wndStyle And WS_HSCROLL) <> 0 Then
which is not a bit-wise comparison, but your code example is If (Style And WS_HSCROLL).

[orange]

Just checked it by setting scrollbars on TestMessage form

0 ---neither
1-- horizontal
2 --vertical
3-- both

[EonsTimE]

I checked your link. VB / VBA often inter-compatible, but not always.
Also of interest is that the page shows this comparison (wndStyle And WS_HSCROLL) <> 0 Then
which is not a bit-wise comparison, but your code example is If (Style And WS_HSCROLL).

It... evolved somehow I wanted to make a function that returns true/false state to be able to call it from other subs and the original code is just a sub that displays msgbox. I carved out most of the stuff from the original sub, but maybe will go back tomorrow and check if it works as is if I just plug it in. Good night ^^