Attribute VB_Name = "modDynamicChange"
Option Explicit
Private Const CCDEVICENAME = 32
Private Const CCFORMNAME = 32
Private Const DISP_CHANGE_SUCCESSFUL = 0
Private Const DISP_CHANGE_RESTART = 1
Private Const DISP_CHANGE_FAILED = -1
Private Const DISP_CHANGE_BADMODE = -2
Private Const DISP_CHANGE_NOTUPDATED = -3
Private Const DISP_CHANGE_BADFLAGS = -4
Private Const DISP_CHANGE_BADPARAM = -5
Private Const CDS_UPDATEREGISTRY = &H1
Private Const CDS_TEST = &H2
Private Const DM_BITSPERPEL = &H40000
Private Const DM_PELSWIDTH = &H80000
Private Const DM_PELSHEIGHT = &H100000
Private Type DEVMODE
dmDeviceName As String * CCDEVICENAME
dmSpecVersion As Integer
dmDriverVersion As Integer
dmSize As Integer
dmDriverExtra As Integer
dmFields As Long
dmOrientation As Integer
dmPaperSize As Integer
dmPaperLength As Integer
dmPaperWidth As Integer
dmScale As Integer
dmCopies As Integer
dmDefaultSource As Integer
dmPrintQuality As Integer
dmColor As Integer
dmDuplex As Integer
dmYResolution As Integer
dmTTOption As Integer
dmCollate As Integer
dmFormName As String * CCFORMNAME
dmUnusedPadding As Integer
dmBitsPerPel As Integer
dmPelsWidth As Long
dmPelsHeight As Long
dmDisplayFlags As Long
dmDisplayFrequency As Long
End Type
Private Declare Function EnumDisplaySettings Lib "user32" Alias "EnumDisplaySettingsA" (ByVal lpszDeviceName As Long, ByVal iModeNum As Long, lpDevMode As Any) As Boolean
Private Declare Function ChangeDisplaySettings Lib "user32" Alias "ChangeDisplaySettingsA" (lpDevMode As Any, ByVal dwflags As Long) As Long
Function ChangeScreenSettings(lWidth As Integer, lHeight As Integer, lColors As Integer)
Dim tDevMode As DEVMODE, lTemp As Long, lIndex As Long
' Declare variables
lIndex = 0
Do
'Instilise Do loop
lTemp = EnumDisplaySettings(0&, lIndex, tDevMode)
' Call the APi function
If lTemp = 0 Then Exit Do
' If there is no more data or an erro occurs
' then return 0 and exit do
lIndex = lIndex + 1
' Increase the index to be enumerated
With tDevMode
If .dmPelsWidth = lWidth And .dmPelsHeight = lHeight And .dmBitsPerPel = lColors Then
lTemp = ChangeDisplaySettings(tDevMode, CDS_UPDATEREGISTRY)
Exit Do
End If
End With
' Set the new data
' Change the display type. This depends on the paramter used
' It can either be:
' 0 - Dynamic change if possible
' CDS_UPDATEREGISTRY - Dynamically change if possible
' and if not possibel then update registry for change
' on the next boot-up
' CDS_TEST - Test the new settings
Loop
Select Case lTemp
' Check for errors
Case DISP_CHANGE_SUCCESSFUL
MsgBox "The display settings change was successful", vbInformation
Case DISP_CHANGE_RESTART
MsgBox "The computer must be restarted in order for the graphics mode to work", vbQuestion
Case DISP_CHANGE_FAILED
MsgBox "The display driver failed the specified graphics mode", vbCritical
Case DISP_CHANGE_BADMODE
MsgBox "The graphics mode is not supported", vbCritical
Case DISP_CHANGE_NOTUPDATED
MsgBox "Unable to write settings to the registry", vbCritical
' NB. Windows NT Only
Case DISP_CHANGE_BADFLAGS
MsgBox "An invalid set of flags was passed in", vbCritical
End Select
End Function
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