VBA API: How to get the monitor number?

Question

Hello,
I have written
an Excel application which
controls an external application
(making inputs,
reads out the window,
etc.).
I use a lot of API functions, e.g. as in the code from thisarticle:
https://support.microsoft.com/en-us/kb/194578?wa=wsignin1.0
A basic
function of my application is
to distinguish between windows
that have the same title
but are on different monitors.
In my windows (and NVIDIA) settings the left monitor is 1 and the right monitor is 2.
In the past I have this routine to "identify" the monitor number from a window handle:
Function GetWindowMonitor(ByVal hWnd As Long) As Integer
Dim hMonitor As Long, MI As MONITORINFO, hM
hMonitor = MonitorFromWindow(hWnd, MONITOR_DEFAULTTONEAREST)
MI.cbSize = Len(MI)
GetMonitorInfo hMonitor, MI
Set mMonitor = New Collection
EnumDisplayMonitors ByVal 0&, ByVal 0&, AddressOf MonitorEnumProc, ByVal 0&
For Each hM In mMonitor
GetWindowMonitor = GetWindowMonitor + 1
If hM = hMonitor Then Exit Function
Next
GetWindowMonitor = 0
End Function
But last week I got a new graphic card and now this obvious stupid function fails, because EnumDisplayMonitors delivers the 2nd monitor first and then the 1st
monitor.
Long talk, short question: Is there any way to get the real monitor numbers as they are shown inside the windows settings?
Andreas.

Answer 1

When you need to identify monitors, call CreateDC with "DISPLAY" as the driver name and pass monitor name as the device name. Then you can draw a number on the result HDC.
I can not draw that number and I can not set an identifier. As I said in my last post:
I share this tool with my colleagues at work.
Okay... CreateDC is an idea... as I've read at MSDN I can call EnumDisplayMonitors with a DC to get informations about the monitor, so I tried the code below, but it doesn't work.
EnumDisplayMonitors does not call my MonitorEnumProc when I call it with a DC.
Do I something wrong? Do I misunderstood the MSDN article? Is that not possible? Can you confirm that?
Andreas.
Option Explicit
Private Declare Function GetForegroundWindow Lib "user32" () As Long
Private Type DISPLAY_DEVICE
cb As Long
DeviceName As String * 32
DeviceString As String * 128
StateFlags As Long
DeviceID As String * 128
DeviceKey As String * 128
End Type
Private Const DISPLAY_DEVICE_MIRRORING_DRIVER = &H8
Private Declare Function EnumDisplayDevicesS Lib "user32" Alias "EnumDisplayDevicesA" ( _
ByVal DeviceName As String, ByVal iDevNum As Long, lpDisplayDevice As _
DISPLAY_DEVICE, ByVal dwFlags As Long) As Long
Private Declare Function CreateDC Lib "gdi32" Alias "CreateDCA" ( _
ByVal lpszDriver As String, ByVal lpszDevice As String, ByVal lpszOutput As Long, _
lpInitData As Any) As Long
Private Declare Function DeleteDC Lib "gdi32" (ByVal hDC As Long) As Long
Private Type RECT
Left As Long
Top As Long
Right As Long
Bottom As Long
End Type
Private Declare Function GetWindowRect Lib "user32" ( _
ByVal hWnd As Long, lpRect As RECT) As Long
Private Declare Function EnumDisplayMonitors Lib "user32.dll" ( _
ByVal hDC As Long, ByRef lprcClip As Any, ByVal lpfnEnum As Long, _
ByVal dwData As Long) As Long
Private Type MONITORINFO
cbSize As Long
rcMonitor As RECT
rcWork As RECT
dwFlags As Long
End Type
Private Declare Function GetMonitorInfo Lib "user32.dll" Alias "GetMonitorInfoA" ( _
ByVal hMonitor As Long, ByRef lpmi As MONITORINFO) As Long
Private Function MonitorEnumProc(ByVal hMonitor As Long, ByVal hdcMonitor As Long, _
lprcMonitor As RECT, ByVal dwData As Long) As Long
Dim MI As MONITORINFO
Debug.Print "Monitor " & hMonitor
GetMonitorInfo hMonitor, MI
With MI.rcMonitor
Debug.Print "Left", "Top", "Right", "Bottom"
Debug.Print .Left, .Top, .Right, .Bottom
End With
'Continue enumeration
MonitorEnumProc = 1
End Function
Function JustNumbers(ByVal What As String) As String
'Return only numbers from What (by Rick Rothstein)
Dim i As Long, j As Long, Digit As String
For i = 1 To Len(What)
Digit = Mid$(What, i, 1)
If Digit Like "#" Then
j = j + 1
Mid$(What, j, 1) = Digit
End If
Next
JustNumbers = Left$(What, j)
End Function
Sub Main()
Dim DD As DISPLAY_DEVICE
Dim DDevice
Dim DDevices As New Collection
Dim DMonitor
Dim DMonitors As New Collection
Dim i As Long, k As Long
Dim hDC As Long
Dim DrvName As String, DevName As String
Dim hWnd As Long, hRECT As RECT
'Get our window handle
hWnd = GetForegroundWindow
'Now I want to know if this window is located on monitor 1 or 2 (or both)
'Get the coordinates of the window
GetWindowRect hWnd, hRECT
With hRECT
Debug.Print "Window:"
Debug.Print "Left", "Top", "Right", "Bottom"
Debug.Print .Left, .Top, .Right, .Bottom
End With
'Get the device drivers
DD.cb = Len(DD)
i = 0
Do While EnumDisplayDevicesS(vbNullString, i, DD, 0&) <> 0
If (DD.StateFlags And DISPLAY_DEVICE_MIRRORING_DRIVER) = 0 Then
k = InStr(DD.DeviceName, vbNullChar)
DDevices.Add Left(DD.DeviceName, k - 1)
End If
i = i + 1
Loop
'2. Get the monitors on each driver
For Each DDevice In DDevices
i = 0
Do While EnumDisplayDevicesS(DDevice & vbNullChar, i, DD, 0&) <> 0
k = InStr(DD.DeviceName, vbNullChar)
DMonitors.Add Left(DD.DeviceName, k - 1)
i = i + 1
Loop
Next
'Create a DC for each monitor and get the coordinates
For Each DMonitor In DMonitors
i = InStrRev(DMonitor, "\")
'"\\.\DISPLAY1"
DrvName = Left(DMonitor, i - 1) & vbNullChar
'"Monitor0"
DevName = Mid(DMonitor, i + 1) & vbNullChar
hDC = CreateDC(DrvName, DevName, 0, ByVal 0&)
Debug.Print DrvName, DevName, hDC
'The driver name is the monitor number!?
EnumDisplayMonitors hDC, ByVal 0&, AddressOf MonitorEnumProc, Val(JustNumbers(DrvName))
DeleteDC hDC
Next
End Sub