Option Explicit
Const WM_DISPLAYCHANGE = &H7E
Const HWND_BROADCAST = &HFFFF&
Const EWX_LOGOFF = 0
Const EWX_SHUTDOWN = 1
Const EWX_REBOOT = 2
Const EWX_FORCE = 4
Const CCDEVICENAME = 32
Const CCFORMNAME = 32
Const DM_BITSPERPEL = &H40000
Const DM_PELSWIDTH = &H80000
Const DM_PELSHEIGHT = &H100000
Const CDS_UPDATEREGISTRY = &H1
Const CDS_TEST = &H4
Const DISP_CHANGE_SUCCESSFUL = 0
Const DISP_CHANGE_RESTART = 1
Const BITSPIXEL = 12
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
Private Declare Function ExitWindowsEx Lib "user32" (ByVal uFlags As Long, ByVal dwReserved As Long) As Long
Private Declare Function GetDeviceCaps Lib "gdi32" (ByVal hdc As Long, ByVal nIndex As Long) As Long
Private Declare Function CreateDC Lib "gdi32" Alias "CreateDCA" (ByVal lpDriverName As String, ByVal lpDeviceName As String, ByVal lpOutput As String, ByVal lpInitData As Any) As Long
Private Declare Function DeleteDC Lib "gdi32" (ByVal hdc As Long) As Long
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
Dim OldX As Long, OldY As Long, nDC As Long
Sub ChangeRes(X As Long, Y As Long, Bits As Long)
Dim DevM As DEVMODE, ScInfo As Long, erg As Long, an As VbMsgBoxResult
'Get the info into DevM
erg = EnumDisplaySettings(0&, 0&, DevM)
'This is what we're going to change
DevM.dmFields = DM_PELSWIDTH Or DM_PELSHEIGHT Or DM_BITSPERPEL
DevM.dmPelsWidth = X 'ScreenWidth
DevM.dmPelsHeight = Y 'ScreenHeight
DevM.dmBitsPerPel = Bits '(can be 8, 16, 24, 32 or even 4)
'Now change the display and check if possible
erg = ChangeDisplaySettings(DevM, CDS_TEST)
'Check if succesfull
Select Case erg&
Case DISP_CHANGE_RESTART
an = MsgBox("You've to reboot", vbYesNo + vbSystemModal, "Info")
If an = vbYes Then
erg& = ExitWindowsEx(EWX_REBOOT, 0&)
End If
Case DISP_CHANGE_SUCCESSFUL
erg = ChangeDisplaySettings(DevM, CDS_UPDATEREGISTRY)
ScInfo = Y * 2 ^ 16 + X
'Notify all the windows of the screen resolution change
SendMessage HWND_BROADCAST, WM_DISPLAYCHANGE, ByVal Bits, ByVal ScInfo
MsgBox "Everything's ok", vbOKOnly + vbSystemModal, "It worked!"
Case Else
MsgBox "Mode not supported", vbOKOnly + vbSystemModal, "Error"
End Select
End Sub
Private Sub Form_Load()
Dim nDC As Long
'retrieve the screen's resolution
OldX = Screen.Width / Screen.TwipsPerPixelX
OldY = Screen.Height / Screen.TwipsPerPixelY
'Create a device context, compatible with the screen
nDC = CreateDC("DISPLAY", vbNullString, vbNullString, ByVal 0&)
'Change the screen's resolution
ChangeRes 640, 480, GetDeviceCaps(nDC, BITSPIXEL)
End Sub
Private Sub Form_Unload(Cancel As Integer)
'restore the screen resolution
ChangeRes OldX, OldY, GetDeviceCaps(nDC, BITSPIXEL)
'delete our device context
DeleteDC nDC
End Sub
Public Const CCHFORMNAME = 32
Public Const CCHDEVICENAME = 32
Public Const DM_BITSPERPEL = &H40000
Public Const DM_PELSWIDTH = &H80000
Public Const DM_PELSHEIGHT = &H100000
Public Const CDS_UPDATEREGISTRY = 1
Public Const CDS_TEST = 2
Type DEVMODE
dmDeviceName As String * CCHDEVICENAME
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 * CCHFORMNAME
dmUnusedPadding As Integer
dmBitsPerPel As Integer
dmPelsWidth As Long
dmPelsHeight As Long
dmDisplayFlags As Long
dmDisplayFrequency As Long
End Type
Declare Function EnumDisplaySettings Lib "user32" Alias "EnumDisplaySettingsA" (ByVal lpszDeviceName As Long, ByVal iModeNum As Long, lpDevMode As Any) As Boolean
Declare Function ChangeDisplaySettings Lib "user32" Alias "ChangeDisplaySettingsA" (lpDevMode As Any, ByVal dwflags As Long) As Long
Option Explicit
Dim nDisplay As Integer, devM() As DEVMODE
Private Sub Command1_Click()
devM(List1.ListIndex).dmFields = DM_PELSWIDTH Or DM_PELSHEIGHT Or DM_BITSPERPEL
If ChangeDisplaySettings(devM(List1.ListIndex), CDS_TEST) = 0 Then
MsgBox "测试成功!"
Else
MsgBox "测试失败!"
End If
End Sub
Private Sub Command2_Click()
devM(List1.ListIndex).dmFields = DM_PELSWIDTH Or DM_PELSHEIGHT Or DM_BITSPERPEL
If ChangeDisplaySettings(devM(List1.ListIndex), 0) = 0 Then
MsgBox "设定成功!"
Else
MsgBox "设定失败!"
End If
End Sub
Private Sub Form_Load()
Dim HasMore As Long, i As Integer
i = 0
Do
ReDim Preserve devM(0 To i)
HasMore = EnumDisplaySettings(0, i, devM(i))
If HasMore = 0 Then Exit Do
If devM(i).dmBitsPerPel = 24 Then
List1.AddItem "全彩" & vbTab & _
devM(i).dmPelsWidth & vbTab & devM(i).dmPelsHeight
Else
List1.AddItem 2 ^ devM(i).dmBitsPerPel & vbTab & _
devM(i).dmPelsWidth & vbTab & devM(i).dmPelsHeight
End If
i = i + 1
Loop
nDisplay = i
End Sub
已经测试
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
Const CCDEVICENAME = 32
Const CCFORMNAME = 32
Const DM_PELSWIDTH = &H80000
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
Dim DevM As DEVMODE
Sub ChangeRes(iWidth As Single, iHeight As Single)
Dim a As Boolean
Dim i As Integer
i = 0
Do
a = EnumDisplaySettings(0&, i, DevM)
i = i + 1
Loop Until (a = False)
Dim b&
DevM.dmFields = DM_PELSWIDTH Or DM_PELSHEIGHT
DevM.dmPelsWidth = iWidth
DevM.dmPelsHeight = iHeight
ChangeDisplaySettings DevM, 0
End Sub
Private Sub Form_Load()
Call ChangeRes(800, 600)
End Sub