Determine if screen is active or not from Windows 8 Registry - windows-8

Question

I am looking at monitors list in
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\DISPLAY
In Windows 7, there are a subkey under each screen node named "Control" that indicate if the screen is active or not.
In Windows 8 there are no such subkey.
How can determine if a monitor is active or not from the Windows 8 registry?

Answer 1

Try this code (I verified this):
Public Function GetMonitorDetails() As List(Of WSGetLoginData.Monitor)
'Open the Display Reg-Key
Dim wmiPNPID As New List(Of String)
Dim mc As System.Management.ManagementClass
Dim moc As ManagementObjectCollection
Dim PathPNPID As String
mc = New ManagementClass("Win32_DesktopMonitor")
moc = mc.GetInstances()
For Each mo In moc
PathPNPID = mo.Item("PNPDeviceID")
If PathPNPID.Trim <> "" AndAlso PathPNPID.Contains("\") Then
PathPNPID = PathPNPID.Substring(PathPNPID.LastIndexOf("\") + 1)
wmiPNPID.Add(PathPNPID.ToUpper)
End If
Next
Dim Display As RegistryKey = Registry.LocalMachine
Dim bFailed As [Boolean] = False
Dim obj_ListMonitor As New List(Of WSGetLoginData.Monitor)
Try
Display = Registry.LocalMachine.OpenSubKey("SYSTEM\CurrentControlSet\Enum\DISPLAY")
Catch
bFailed = True
End Try
If Not bFailed And (Display IsNot Nothing) Then
'Get all MonitorIDss
For Each sMonitorID As String In Display.GetSubKeyNames()
Dim MonitorID As RegistryKey = Display.OpenSubKey(sMonitorID)
If MonitorID IsNot Nothing Then
'Get all Plug&Play ID's
For Each sPNPID As String In MonitorID.GetSubKeyNames()
Dim PnPID As RegistryKey = MonitorID.OpenSubKey(sPNPID)
If PnPID IsNot Nothing Then
Dim sSubkeys As String() = PnPID.GetSubKeyNames()
'Check if Monitor is active
'If Array.IndexOf(sSubkeys, "Control") > -1 Then
If Not wmiPNPID Is Nothing AndAlso wmiPNPID.Count > 0 AndAlso wmiPNPID.Contains(sPNPID.ToUpper) Then
If Array.IndexOf(sSubkeys, "Device Parameters") > -1 Then
Dim DevParam As RegistryKey = PnPID.OpenSubKey("Device Parameters")
Dim sSerial As String = ""
Dim sModel As String = ""
'Define Search Keys
Dim sSerFind As New String(New Char() {ChrW(0), ChrW(0), ChrW(0), ChrW(&HFF)})
Dim sModFind As New String(New Char() {ChrW(0), ChrW(0), ChrW(0), ChrW(&HFC)})
'Get the EDID code
Dim bObj As Byte() = TryCast(DevParam.GetValue("EDID", Nothing), Byte())
If bObj IsNot Nothing Then
'Get the 4 Vesa descriptor blocks
Dim sDescriptor As String() = New String(3) {}
sDescriptor(0) = Encoding.[Default].GetString(bObj, &H36, 18)
sDescriptor(1) = Encoding.[Default].GetString(bObj, &H48, 18)
sDescriptor(2) = Encoding.[Default].GetString(bObj, &H5A, 18)
sDescriptor(3) = Encoding.[Default].GetString(bObj, &H6C, 18)
'Search the Keys
For Each sDesc As String In sDescriptor
If sDesc.Contains(sSerFind) Then
sSerial = sDesc.Substring(4).Replace(vbNullChar, "").Trim()
End If
If sDesc.Contains(sModFind) Then
sModel = sDesc.Substring(4).Replace(vbNullChar, "").Trim()
End If
Next
End If
If Not String.IsNullOrEmpty(sSerial) AndAlso sSerial.Trim <> "" Then
Dim insertar As Boolean = True
If Not obj_ListMonitor Is Nothing AndAlso obj_ListMonitor.Count > 0 Then
For k As Integer = 0 To obj_ListMonitor.Count - 1
If obj_ListMonitor(k).SerialNumber.Trim = sSerial Then
insertar = False
Exit For
End If
Next
End If
If insertar Then
Dim obj_monitor As New WSGetLoginData.Monitor
obj_monitor.UUID = Security.FingerPrint.Value(sModel & sSerial)
obj_monitor.Modelo = sModel
obj_monitor.SerialNumber = sSerial
obj_ListMonitor.Add(obj_monitor)
End If
End If
End If
End If
End If
Next
End If
Next
End If
Return obj_ListMonitor
End Function