simply changing the screen reselution

[dimava]

I currently have this in a model:

Option Explicit

Private Declare Function GetSystemMetrics Lib "user32" (ByVal nIndex As Long) As Long

Private Const SM_CXSCREEN = 0
Private Const SM_CYSCREEN = 1

' Check whether screen resolution is set to 640x480
' Returns True if the resolution is at 640x480 else
' False is returned
Public Function GetScreenResolution640x480() As Boolean
Dim lTemp As String
' Temporary string to hold returned screen
' resolution
lTemp = GetSystemMetrics(SM_CXSCREEN) & "x" & GetSystemMetrics(SM_CYSCREEN)
' Call the API function twice to return
' screen size for each axis as format into
' the temporary string
If lTemp = "640x480" Then
  ' Check whether resolution is set to 640x480
  GetScreenResolution640x480 = True
  ' True
Else
  GetScreenResolution640x480 = False
  ' False
End If
End Function

and in the form load it says:

If GetScreenResolution640x480 = True Then
end
End If

now is there a simple command that changes there screen to 800 X 600

or do I have to use what I downloaded from vb world

thanks in advance

The above code does not change the resolution, rather, it check what it is. See this tip for information on changing the resolution.

If your question was, 'How can I check if it's 800x600', you can simply change If lTemp = "640x480" Then to If lTemp = "800x600" Then.

[dimava]

when I try that tip it doesn't work
I got errors in the Basic Module

and my code just checks to see if its 600x800 thats all it doesn't change the reselution


any other ideas?

Author may have messed up a little. I have modified the code so it will work.

Put this in a Module

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
Declare Function ExitWindowsEx Lib "user32" (ByVal uFlags As Long, ByVal dwReserved As Long) As Long
Public Const EWX_LOGOFF = 0
Public Const EWX_SHUTDOWN = 1
Public Const EWX_REBOOT = 2
Public Const EWX_FORCE = 4
Public Const CCDEVICENAME = 32
Public Const CCFORMNAME = 32
Public Const DM_BITSPERPEL = &H40000
Public Const DM_PELSWIDTH = &H80000
Public Const DM_PELSHEIGHT = &H100000
Public Const CDS_UPDATEREGISTRY = &H1
Public Const CDS_TEST = &H4
Public Const DISP_CHANGE_SUCCESSFUL = 0
Public Const DISP_CHANGE_RESTART = 1
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

Put this in a CommandButton

Private Sub Command1_Click()

    Dim DevM As DEVMODE
    'Get the info into DevM
    erg& = EnumDisplaySettings(0&, 0&, DevM)
    'We don't change the colordepth, because a
    'rebot will be necessary
    
    DevM.dmFields = DM_PELSWIDTH Or DM_PELSHEIGHT 'Or DM_BITSPERPEL
    DevM.dmPelsWidth = 640 'ScreenWidth
    DevM.dmPelsHeight = 480 'ScreenHeight
    DevM.dmBitsPerPel = 32 '(could be 8, 16, 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)
        MsgBox "Everything's ok", vbOKOnly + vbSystemModal, "It worked!"
    Case Else
        MsgBox "Mode not supported", vbOKOnly + vbSystemModal, "Error"
    End Select
    
End Sub

[dimava]

thanks megatron

[dimava]

when I run the program with my screen size as 640 x 480
an error allways comes up at
erg&

You can change the Width and Height by modifing these lines.

DevM.dmPelsWidth = 640 'ScreenWidth
DevM.dmPelsHeight = 480 'ScreenHeight

What is the description of your Error?

[dimava]

yea I know, I did edit that, I changed it to 800 * 600


then I put my monitors reselution to 640 * 480

then an error came up

and when I click DebUG the it highlights erg&
then it says varaible not defined