'werte für devmode.dmFields
    <Flags()> _
    Enum DM As Integer
        Orientation = &H1
        PaperSize = &H2
        PaperLength = &H4
        PaperWidth = &H8
        Scale = &H10
        Position = &H20I
        NUP = &H40
        DisplayOrientation = &H80
        Copies = &H100
        DefaultSource = &H200
        PrintQuality = &H400
        Color = &H800
        Duplex = &H1000
        YResolution = &H2000
        TTOption = &H4000
        Collate = &H8000
        FormName = &H10000
        LogPixels = &H20000
        BitsPerPixel = &H40000
        PelsWidth = &H80000
        PelsHeight = &H100000
        DisplayFlags = &H200000
        DisplayFrequency = &H400000
        ICMMethod = &H800000
        ICMIntent = &H1000000
        MediaType = &H2000000
        DitherType = &H4000000
        PanningWidth = &H8000000
        PanningHeight = &H10000000
        DisplayFixedOutput = &H20000000
    End Enum
 
 
    'rückgabewert der Funktion ChangeDisplaySettingsEx
    Enum DISP_CHANGE As Integer
        Successful = 0
        Restart = 1
        Failed = -1
        BadMode = -2
        NotUpdated = -3
        BadFlags = -4
        BadParam = -5
        BadDualView = -1
    End Enum
 
 
 
 
    'wird noch nicht genutzt vlt später mal
    'für das struct DISPLAY_DEVICE und somit für die Funktion EnumDisplayDevices
    <Flags()> _
    Enum DisplayDeviceStateFlags As Integer
        AttachedToDesktop = &H1
        MultiDriver = &H2
        PrimaryDevice = &H4
        MirroringDriver = &H8
        VGACompatible = &H16
        Removable = &H20
        ModesPruned = &H8000000
        Remote = &H4000000
        Disconnect = &H2000000
    End Enum
 
    'für die Funktion EnumDisplayDevices
    <StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Ansi)> _
    Public Structure DISPLAY_DEVICE
        <MarshalAs(UnmanagedType.U4)> _
        Public cb As Integer
        <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=32)> _
        Public DeviceName As String
        <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=128)> _
        Public DeviceString As String
        <MarshalAs(UnmanagedType.U4)> _
        Public StateFlags As DisplayDeviceStateFlags
        <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=128)> _
        Public DeviceID As String
        <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=128)> _
        Public DeviceKey As String
    End Structure
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
 
    End Sub
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button1.Click
        Dim par = Environment.GetCommandLineArgs()
        'RichTextBox1.Text = par
        Dim returnval As Long
        Dim dev, dev1 As DEVMODE
        Dim i, monitore As Long
        Dim d As DISPLAY_DEVICE
 
        dev.dmSize = Len(dev)
        dev.dmFields = DM_BITSPERPEL Or DM_PELSWIDTH Or DM_PELSHEIGHT Or _
          DM_DISPLAYFREQUENCY Or DM_DISPLAYFLAGS Or DM.Position Or _
          DM.DisplayFlags
 
        'wie viele monitore?
        d.cb = Marshal.SizeOf(d)
        Do While EnumDisplayDevices(Nothing, i, d, 0) << 0
            RichTextBox1.Text = RichTextBox1.Text & d.DeviceName & " | " & _
              d.StateFlags & " | " & vbCrLf
            i = i + 1
        Loop
        'wie viele monitore  keine virtuellen
        i = 1
        Do While EnumDisplaySettings("\\.\DISPlAY" & i, 0, dev) << 0
            monitore = CStr(i)
            i = i + 1
        Loop
 
 
 
 
        EnumDisplaySettings("\\.\DISPlAY2", 0, dev)
        dev.dmPelsWidth = 1600
        dev.dmPelsHeight = 1200
        dev.dmDisplayFrequency = 60
        dev.dmBitsPerPel = 32
        'dev.dmDisplayFlags = 32
        'dev.dmDisplayFlags = 0
 
        dev.dmPositionX = 0
        dev.dmPositionY = Screen.PrimaryScreen.Bounds.Bottom
        dev.dmPosition.x = 0
        dev.dmPosition.y = Screen.PrimaryScreen.Bounds.Bottom
 
 
        Dim lResult As Integer
 
 
        lResult = ChangeDisplaySettingsEx("\\.\DISPLAY2", dev, IntPtr.Zero, _
          CDS_TEST, IntPtr.Zero)
 
        If lResult = 0 Then ChangeDisplaySettingsEx("\\.\DISPLAY2", dev, _
          IntPtr.Zero, CDS_RESET, IntPtr.Zero) 'MsgBox("juhuuu")
 
    End Sub