Hi,

Not sure how useful this is to anyone but I had alot of trouble finding a VB.NET Screen Resolution Change functionality, so I managed to get it working, and the code is below.

Can be called by: ChangeRes(1024,768)

Any comments are welcome, as are bug fixes!!!!

VB Code:
  1. Imports System.Runtime.InteropServices

  2.  
  3. Public Module resChanger

  4.  
  5.     Const ENUM_CURRENT_SETTINGS As Integer = -1

  6.     Const CDS_UPDATEREGISTRY As Integer = &H1

  7.     Const CDS_TEST As Long = &H2

  8.  
  9.     Const CCDEVICENAME As Integer = 32

  10.     Const CCFORMNAME As Integer = 32

  11.  
  12.     Const DISP_CHANGE_SUCCESSFUL As Integer = 0

  13.     Const DISP_CHANGE_RESTART As Integer = 1

  14.     Const DISP_CHANGE_FAILED As Integer = -1

  15.  
  16.     Private Declare Function EnumDisplaySettings Lib "user32" Alias "EnumDisplaySettingsA" (ByVal lpszDeviceName As Integer, ByVal iModeNum As Integer, ByRef lpDevMode As DEVMODE) As Integer

  17.     Private Declare Function ChangeDisplaySettings Lib "user32" Alias "ChangeDisplaySettingsA" (ByRef DEVMODE As DEVMODE, ByVal flags As Long) As Integer

  18.  
  19.     <StructLayout(LayoutKind.Sequential)> Public Structure DEVMODE

  20.         <MarshalAsAttribute(UnmanagedType.ByValTStr, SizeConst:=CCDEVICENAME)> Public dmDeviceName As String

  21.         Public dmSpecVersion As Short

  22.         Public dmDriverVersion As Short

  23.         Public dmSize As Short

  24.         Public dmDriverExtra As Short

  25.         Public dmFields As Integer

  26.         Public dmOrientation As Short

  27.         Public dmPaperSize As Short

  28.         Public dmPaperLength As Short

  29.         Public dmPaperWidth As Short

  30.         Public dmScale As Short

  31.         Public dmCopies As Short

  32.         Public dmDefaultSource As Short

  33.         Public dmPrintQuality As Short

  34.         Public dmColor As Short

  35.         Public dmDuplex As Short

  36.         Public dmYResolution As Short

  37.         Public dmTTOption As Short

  38.         Public dmCollate As Short

  39.         <MarshalAsAttribute(UnmanagedType.ByValTStr, SizeConst:=CCFORMNAME)> Public dmFormName As String

  40.         Public dmUnusedPadding As Short

  41.         Public dmBitsPerPel As Short

  42.         Public dmPelsWidth As Integer

  43.         Public dmPelsHeight As Integer

  44.         Public dmDisplayFlags As Integer

  45.         Public dmDisplayFrequency As Integer

  46.     End Structure

  47.  
  48.     Public Sub changeRes(ByVal theWidth As Integer, ByVal theHeight As Integer)

  49.  
  50.         Dim DevM As DEVMODE

  51.  
  52.         DevM.dmDeviceName = New [String](New Char(32) {})

  53.         DevM.dmFormName = New [String](New Char(32) {})

  54.         DevM.dmSize = CShort(Marshal.SizeOf(GetType(DEVMODE)))

  55.  
  56.  
  57.         If 0 <> EnumDisplaySettings(Nothing, ENUM_CURRENT_SETTINGS, DevM) Then

  58.             Dim lResult As Integer

  59.  
  60.             DevM.dmPelsWidth = theWidth

  61.             DevM.dmPelsHeight = theHeight

  62.             DevM.dmPelsWidth = 1280

  63.             DevM.dmPelsHeight = 1024

  64.  
  65.             lResult = ChangeDisplaySettings(DevM, CDS_TEST)

  66.  
  67.             If lResult = DISP_CHANGE_FAILED Then

  68.                 MsgBox("Display Change Failed.", MsgBoxStyle.OKOnly + MsgBoxStyle.Critical, "Screen Resolution Change Failed")

  69.             Else

  70.  
  71.                 lResult = ChangeDisplaySettings(DevM, CDS_UPDATEREGISTRY)

  72.  
  73.                 Select Case lResult

  74.                     Case DISP_CHANGE_RESTART

  75.                         MsgBox("You must restart your computer to apply these changes.", MsgBoxStyle.OKOnly + MsgBoxStyle.Critical, "Screen Resolution Has Changed")

  76.                     Case DISP_CHANGE_SUCCESSFUL

  77.                         MsgBox("Display Change Successful.", MsgBoxStyle.OKOnly + MsgBoxStyle.Information, "Screen Resolution Successful")

  78.                     Case Else

  79.                         MsgBox("Display Change Failed.", MsgBoxStyle.OKOnly + MsgBoxStyle.Critical, "Screen Resolution Change Failed")

  80.                 End Select

  81.             End If

  82.  
  83.  
  84.         End If

  85.     End Sub

  86.  
  87. End Module