Rough Notes, and posts to be referenced from elsewhere, on VBA Windows API

**DocAElstein** · 11-12-2024, 08:16 PM

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This is post #11 forum post24916
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Some notes, codings etc. in support of some other posts
https://eileenslounge.com/viewtopic....321979#p321979
https://www.excelfox.com/forum/showt...ll=1#post24904

Getting some windows identification info

.
Main coding courtesy of Dev Ashish, http://access.mvps.org/access/api/api0013.htm
( and https://eileenslounge.com/viewtopic....321978#p321978 )
I did some minor adjustments, mostly in output to suit my own experiments

Code:

' Original main Code Courtesy of Dev Ashish  http://access.mvps.org/access/api/api0013.htm  and  https://eileenslounge.com/viewtopic.php?p=321978#p321978
'
Private Declare Function apiGetClassName Lib "user32" Alias "GetClassNameA" (ByVal Hwnd As Long, ByVal lpClassName As String, ByVal nMaxCount As Long) As Long
Private Declare Function apiGetDesktopWindow Lib "user32" Alias "GetDesktopWindow" () As Long
Private Declare Function apiGetWindow Lib "user32" Alias "GetWindow" (ByVal Hwnd As Long, ByVal wCmd As Long) As Long
Private Declare Function apiGetWindowLong Lib "user32" Alias "GetWindowLongA" (ByVal Hwnd As Long, ByVal nIndex As Long) As Long
Private Declare Function apiGetWindowText Lib "user32" Alias "GetWindowTextA" (ByVal Hwnd As Long, ByVal lpString As String, ByVal aint As Long) As Long
Private Declare Function FindWndNumber Lib "user32" Alias "FindWindowA" (Optional ByVal lpClassName As String, Optional ByVal lpWindowName As String) As Long
Private Const mcGWCHILD = 5
Private Const mcGWHWNDNEXT = 2
Private Const mcGWLSTYLE = (-16)
Private Const mcWSVISIBLE = &H10000000 '  Watch window gives  268435456 (even when no code is running)
Private Const mconMAXLEN = 255

Public Sub fEnumWindows()
' For worksheet output, not important for understanding the main coding
Dim Ws As Worksheet: Set Ws = ThisWorkbook.Worksheets.Item(1)
Dim Lc As Long, Lr As Long: Let Lc = Ws.Cells.Item(2, Ws.Columns.Count).End(xlToLeft).Column
 Let Ws.Cells.Item(1, Lc + 1) = CreateObject("WScript.Network").ComputerName & "      " & Format(Now(), "ddd,dd,mmm,yyyy")                  '  Environ$("computername")      Nigel Heffernan  https://stackoverflow.com/questions/3551055/how-to-get-name-of-the-computer-in-vba/10108951#10108951
 Let Ws.Cells.Item(2, Lc + 1) = "Hwnd": Let Ws.Cells.Item(2, Lc + 2) = "Class Name": Let Ws.Cells.Item(2, Lc + 3) = "Caption": Let Ws.Cells.Item(2, Lc + 4) = "Hwnd( Caption)": Let Ws.Cells.Item(2, Lc + 5) = "enum visible?"


Dim lngx As Long, lngLen As Long, lngStyle As Long, strCaption As String
 Let lngx = apiGetDesktopWindow(): Debug.Print "Geted Desktop Window  " & lngx & " " & " CLass name " & fGetClassName(lngx)
 Let lngx = apiGetWindow(lngx, mcGWCHILD): Debug.Print "   First child to Desktop " & lngx & " CLass name " & fGetClassName(lngx) '   GW_CHILD = 5    The topmost of the given window's child windows. This has the same effect as using the GetTopWindow function, ... usually at the top of all the other children in the Z-order
    Do While Not lngx = 0 ' We are looping "equal level children", seperated not realy, just look seperate to us because of the seen to us z order
     Let strCaption = fGetCaption(lngx)
'        If Len(strCaption) > 0 Then ' Those without a caption seem not important
         Let lngStyle = apiGetWindowLong(lngx, mcGWLSTYLE) '  apiGetWindowLong gets info,   GWL_STYLE  -16  retrieves the window styles
            ' For   enum visible windows only
'            If lngStyle And mcWSVISIBLE Then   '
             Let Lr = Ws.Cells.Item(Ws.Rows.Count, Lc + 1).End(xlUp).Row                                                    '  Handle             Class name          Caption
                If lngStyle And mcWSVISIBLE Then
                 Let Ws.Cells.Item(Lr + 1, Lc + 5) = "enum visible " & lngStyle & " And " & mcWSVISIBLE
                Else
                 'Let Ws.Cells.Item(Lr + 1, Lc + 5) = lngStyle & " And " & mcWSVISIBLE
                End If
             Let Ws.Cells.Item(Lr + 1, Lc + 6) = lngStyle: Ws.Cells.Item(Lr + 1, Lc + 7) = mcWSVISIBLE
             Debug.Print FindWndNumber(lpClassName:=fGetClassName(lngx), lpWindowName:=vbNullString), fGetClassName(lngx); Tab(50); fGetCaption(lngx); Tab(100); FindWndNumber(lpClassName:=vbNullString, lpWindowName:=fGetCaption(lngx))
             Let Ws.Cells.Item(Lr + 1, Lc + 1) = lngStyle & " " & FindWndNumber(lpClassName:=fGetClassName(lngx)): Let Ws.Cells.Item(Lr + 1, Lc + 2) = fGetClassName(lngx): Let Ws.Cells.Item(Lr + 1, Lc + 3) = fGetCaption(lngx): Let Ws.Cells.Item(Lr + 1, Lc + 4) = FindWndNumber(lpClassName:=vbNullString, lpWindowName:=fGetCaption(lngx))
'            End If
'        End If
     Let lngx = apiGetWindow(lngx, mcGWHWNDNEXT) '  GW_HWNDNEXT = 2   The window below the given window in the Z-order.
    Loop ' While Not lngx = 0  ' I am going through all the child windows of the desktop windows
End Sub
Private Function fGetCaption(Hwnd As Long) As String
Dim strBuffer As String, intCount As Integer
 Let strBuffer = String$(Number:=255 - 1, Character:="0") ' "00000000000000000000000000000000..........000"
 Let intCount = apiGetWindowText(Hwnd:=Hwnd, lpString:=strBuffer, aint:=255) ' This makes  strBuffer  something like    *MSCTFIME UI 0000000000000000............000"
    If intCount > 0 Then Let fGetCaption = Left$(strBuffer, intCount)
End Function
Private Function fGetClassName(Hwnd As Long) As String
Dim strBuffer As String, intCount As Integer
 Let strBuffer = String$(255 - 1, 0)
 Let intCount = apiGetClassName(Hwnd, strBuffer, mconMAXLEN)
    If intCount > 0 Then
     Let fGetClassName = Left$(strBuffer, intCount)
    End If
End Function

**DocAElstein** · Today, 02:39 AM

If lngStyle And mcWSVISIBLE Then
Some notes, codings etc. in support of some other posts
https://eileenslounge.com/viewtopic....321979#p321979 https://eileenslounge.com/viewtopic.php?f=30&t=41610
https://www.excelfox.com/forum/showt...l=1#post249016

Introduction
A code line from the last post , If lngStyle And mcWSVISIBLE Then
What’s going on? – Hans told me …. The number is looked at by VBA in its binary representation form, and each corresponding Bit at the same horizontal position for the two numbers is compared. This is referred to as bitwise AND of the binary representation of the numbers. If at any position both are 1 , then the result will be true…..

It all started here:
I had some strange results that I did not understand. It boiled down to some code lines such as this returning True
If -1811939328 And 268435456 Then
, whilst similar such as this returning False
If -2046820352 And 268435456 Then

So, because ExcelFox is the adult thinking man’s forum, we are going to have a good look at it.

String like 0 1 representation of a number
A couple of points to consider
_(i) A string type representation of a lot of 0s and 1s is a good idea so that we don’t have problems with things like leading 0s vanishing when Excel or VBA messes with the format of a number we may write: In binary computer things the number will have typically some fixed character length, so we should not mess with that, or let Excel or VBA mess with it
_(ii) The first Bit/first position is always reserved for the sign character, (which is 1 for a negative number, and that leads to the phenomena that Anding two negative numbers always results in a True, - it's an artefact of that the first digit is also included in the bitwise AND of the binary representation of the numbers.

A simple function to get the string like binary 0s and 1s representation of a number.
We decide on some length limit for the string. For now, based on an initial quick empirical look and guess, I will go for up to 30 powers of 2, ( (2 ^ N) = (2 ^ 30) ). I might change that later based on experience. A big one initially will hopefully catch numbers as big as we have. This means the string length will be 32 characters, as in the string like binary 0s and 1s representation we have (2 ^ 0) at the right, (2 ^ 30) at the left, and also an extra sign bit included to be the first left character.
A simple function can be one that builds the string
, first with a 0 or 1 depending on if the decimal number being converted is negative or positive
, then we successively divide the number by (2 ^ N) where N goes from 30 to 0. If the result of the division results in 1 or 1 and a fraction more, we add** ( ** add as in including another character, not maths add ) a 1 to the string, and reduce the decimal number by that (2 ^ N) before moving to the next N. If the division resilts in less than 1, we add a 0, then move on to the next N

Code:

Sub TestNumberInBinary()
Debug.Print NumberInBinary(9)         ' 00000000000000000000000000001001
Debug.Print NumberInBinary(268435456) ' 00010000000000000000000000000000
End Sub
Public Function NumberInBinary(ByVal DecNumber As Long) As String
Rem 1 A negative number in a computer binary representation has a  1  at the first character position
 Let NumberInBinary = IIf(DecNumber < 0, "1", "0")
Rem 2  we successively divide the number by (2 ^ N) where N goes from 30 to 0. If the result of the division results in 1 or 1 and a fraction more, we add** ( ** add as in including another character, not maths add ) a 1 to the string, and reduce the decimal number by that (2 ^ N) before moving to the next N. If the division resilts in less than 1, we add a 0, then move on to the next N Divide the decimal number by 2 to the power of N, with N geting smaller. Every tine the resulting number is equal or bigger than 1  the binary bit would be 1 and the decimal number we reduce by that 2 to the N, and keep going
Dim N As Long
    For N = 30 To 0 Step -1  '  30 seems to be the limit before something is too big
        If DecNumber / (2 ^ N) >= 1 Then
         Let NumberInBinary = NumberInBinary & "1"
         Let DecNumber = DecNumber - (2 ^ N)
        Else
         Let NumberInBinary = NumberInBinary & "0"
        End If
    Next N
End Function

A function to mimic the behaviour of the VBA And with numbers is very easy.
Simply
_ convert the two decimal numbers to a string in the form of the computer binary 0s and 1s representation
_ then starting from the left compare the characters in the corresponding position in the two strings. As soon as you get a 1 in both , you make the functions returned output as True and exit the function, otherwise the function returns false if you never get a pair of 1s

Code:

Public Function NumbersInVBAIf_And_Then(ByVal Dec1 As Long, Dec2 As Long) As Boolean
Rem 1 the two decimal numbers to a string in the form of the computer binary 0s and 1s representation
Dim Bin1 As String, Bin2 As String ' String representation helps prevent loosing leading 0's
 Let Bin1 = NumberInBinary(Dec1): Bin2 = NumberInBinary(Dec2)
Rem 2 starting from the left compare the characters in the corresponding position in the two strings. As soon as you get a 1 in both , you make the functions returned output as True and exit the function, otherwise the function returns false if you never get a pair of 1s
Dim TPwr As Long
    For TPwr = 1 To 32 Step 1
     If Mid(Bin1, TPwr, 1) = 1 And Mid(Bin2, TPwr, 1) = 1 Then Let NumbersInVBAIf_And_Then = True: Exit Function
    Next TPwr
End Function