Changing screen resolution with VB 2005

Question

I'm having a difficult time converting a Windows API call that works fine in VB6 to run in VB 2005 (Windows XP with SP2 in both cases).  I reduced the problem code down to its core which is below. I'm trying to change the screen resolution with the ChangeDisplaySettingsEx call; the idea is that on entering the program it shifts to high resolution and at the end it restores the original settings. I left the restore part out because I get the same error. Which is "An invalid parameter was passed in. This can include an invalid flag or combination of flags."  I'm trying to use exactly the same parameters, but somewhere in the conversion process from VB6 a fatal change crept in.  My guess is that it's either in the ByRef/ByVal or Short/Integer/Long alternatives, or in the conversion of the Devmode structure which included fixed-length strings (OK in VB6 but not allowed in VB.NET). But all my fiddling so far has not produced a solution.  I got the same error code back in VB6 when I tried to set a display frequency that was not supported at the resolution I requested, but even leaving the values unmodified (in effect setting them to what they are now, with no change) gives the same error. Any ideas? So far as I can tell, there is no alternative to the API to accomplish this goal; would be interested to know if I missed it.

'  ==========================
'Imports System, .Drawing, .Windows.Forms
Public Class frmDX9RKS
    Inherits Form
 '==== screen-resolution API, constants, etc. ====

  Public Declare Function ChangeDisplaySettingsEx Lib "user32" _
    Alias "ChangeDisplaySettingsExA" _
    (ByRef lpszDeviceName As Integer, _
     ByRef lpDevMode As DEVMODE, _
     ByVal hWnd As Integer, _
     ByVal dwFlags As Integer, _
     ByRef lParam As Integer) As Integer

  Const CCDEVICENAME As Integer = 32
  Const CCFORMNAME As Integer = 32

  Enum CDSXRC As Integer 'change-display-settings return codes
    'From winuser.h
    DISP_CHANGE_SUCCESSFUL = 0
    DISP_CHANGE_RESTART = 1
    DISP_CHANGE_FAILED = -1
    DISP_CHANGE_BADMODE = -2
    DISP_CHANGE_NOTUPDATED = -3
    DISP_CHANGE_BADFLAGS = -4
    DISP_CHANGE_BADPARAM = -5
  End Enum

  Public Structure DEVMODE
    <VBFixedString(CCDEVICENAME), _
      System.Runtime.InteropServices.MarshalAs( _
      System.Runtime.InteropServices.UnmanagedType.ByValArray, _
      SizeConst:=(CCDEVICENAME))> Public dmDeviceName() As Char
    Dim dmSpecVersion As Short
    Dim dmDriverVersion As Short
    Dim dmSize As Short
    Dim dmDriverExtra As Short
    Dim dmFields As Integer
    Dim dmOrientation As Short
    Dim dmPaperSize As Short
    Dim dmPaperLength As Short
    Dim dmPaperWidth As Short
    Dim dmScale As Short
    Dim dmCopies As Short
    Dim dmDefaultSource As Short
    Dim dmPrintQuality As Short
    Dim dmColor As Short
    Dim dmDuplex As Short
    Dim dmYResolution As Short
    Dim dmTTOption As Short
    Dim dmCollate As Short
    <VBFixedString(CCFORMNAME), _
      System.Runtime.InteropServices.MarshalAs( _
      System.Runtime.InteropServices.UnmanagedType.ByValArray, _
      SizeConst:=(CCFORMNAME))> Public dmFormName() As Char
    Dim dmUnusedPadding As Short
    Dim dmBitsPerPel As Short
    Dim dmPelsWidth As Integer
    Dim dmPelsHeight As Integer
    Dim dmDisplayFlags As Integer
    Dim dmDisplayFrequency As Integer
    Dim dmICMMethod As Integer 'NT 4.0
    Dim dmICMIntent As Integer 'NT 4.0
    Dim dmMediaType As Integer 'NT 4.0
    Dim dmDitherType As Integer 'NT 4.0
    Dim dmReserved1 As Integer 'NT 4.0
    Dim dmReserved2 As Integer 'NT 4.0
    Dim dmPanningWidth As Integer 'Win2000
    Dim dmPanningHeight As Integer 'Win2000
  End Structure

  Public Declare Function EnumDisplaySettings Lib "user32" _
    Alias "EnumDisplaySettingsA" ( _
    ByVal lpszDeviceName As Integer, _
    ByVal iModeNum As Integer, _
    ByRef lpDevMode As DEVMODE) As Boolean

Shared Sub Main()
  Dim frm As New frmDX9RKS()
End Sub    'Main

Public Sub New()
  Const DM_PELSWIDTH As Integer = &H80000
  Const DM_PELSHEIGHT As Integer = &H100000
  Const DM_DISPLAYFREQUENCY As Integer = &H400000
  Const CDS_TEST As Integer = &H4

  InitializeComponent()  'required by the Windows Form Designer.
  ' Add any initialization after the Initialize-Component() call.

    Const HiResW As Integer = 1600 'hi-res width in pixels
    Const HiResH As Integer = 1200 'hi-res height in pixels
    Const ENUM_CURRENT_SETTINGS As Integer = -1

    Static OldWd As Integer 'screen width in pixels
    Static OldHt As Integer 'screen height in pixels
    Static OldFreq As Integer 'screen-refresh frequency

    Dim DevM As New DEVMODE  'added New in V3.2, 3/22/06
    Dim boRetn As Boolean 'boolean return code
    Dim ResChgRtCd As Integer 'As CDSXRC 'resolution-change return code

Debug.Print("Original - width: " & DevM.dmPelsWidth & _
"  Height: " & DevM.dmPelsHeight & _
"  Freq: " & DevM.dmDisplayFrequency & _
"  DevmodeSize: " & DevM.dmSize & _
"  dmFields: " & DevM.dmFields)

    DevM.dmSize = CShort(Len(DevM)) 'set up dev-mode
      'set field bits: Horiz, Vert, Freq
    DevM.dmFields = DM_PELSWIDTH Or DM_PELSHEIGHT Or DM_DISPLAYFREQUENCY

      'save orig values and set to high resolution
      boRetn = EnumDisplaySettings(0, ENUM_CURRENT_SETTINGS, DevM)
Debug.Print("Color: " & DevM.dmBitsPerPel & " bits/pixel")

      OldWd = DevM.dmPelsWidth 'save orig width in pixels
      OldHt = DevM.dmPelsHeight 'save orig height in pixels
      OldFreq = DevM.dmDisplayFrequency 'save orig refresh freq
      DevM.dmPelsWidth = HiResW
      DevM.dmPelsHeight = HiResH
      DevM.dmDisplayFrequency = 60 'use lower (hard-coded) freq for LCD hi-res
Debug.Print("Before change - width: " & DevM.dmPelsWidth & _
"  Height: " & DevM.dmPelsHeight & _
"  Freq: " & DevM.dmDisplayFrequency & _
"  DevmodeSize: " & DevM.dmSize & _
"  dmFields: " & DevM.dmFields)
'Stop
      ResChgRtCd = ChangeDisplaySettingsEx(0, DevM, 0, CDS_TEST, 0)

      If ResChgRtCd <> CDSXRC.DISP_CHANGE_SUCCESSFUL Then 'if change failed,
        subBadResChgDiag((ResChgRtCd)) ' tell why
        Stop
        Exit Sub
      End If

End Sub

Private Sub subBadResChgDiag(ByRef CDSRetCode As Integer)
  Dim strErr As String
  Dim strBase As String

  strBase = "Screen-resolution change failed;" & vbCrLf & vbCrLf & "Code is: "

  Select Case CDSRetCode
    Case CDSXRC.DISP_CHANGE_RESTART
      strErr = strBase & "CHANGE_RESTART"
    Case CDSXRC.DISP_CHANGE_FAILED
      strErr = strBase & "CHANGE_FAILED"
    Case CDSXRC.DISP_CHANGE_BADMODE
      strErr = strBase & "CHANGE_BADMODE"
    Case CDSXRC.DISP_CHANGE_NOTUPDATED
      strErr = strBase & "CHANGE_NOTUPDATED"
    Case CDSXRC.DISP_CHANGE_BADFLAGS
      strErr = strBase & "CHANGE_BADFLAGS"
    Case CDSXRC.DISP_CHANGE_BADPARAM
      strErr = strBase & "CHANGE_BADPARAM"
    Case Else
      strErr = strBase & "Unknown resolution-change error"
  End Select
  MsgBox(strErr)

End Sub

End Class

Answer 1

Just forget trying to use the API to change the display mode. Instead:

1. Add a COM reference to 'DirectX 7 for Visual Basic Type library'

2. At the top of your code for your main form, before the class declaration, add 'Imports DxVbLib'

3. After the class declaration, add:

     Dim dx as New DirectX7

     Dim dd as DirectDraw7

4. Add the following code to your Form_Load event handler:

    dd=dx.DirectDrawCreate("")

    dd.setDisplayMode(800,600,16,0,CONST_DDSDMFLAGS.DDSDM_DEFAULT)

Note: Change '800' to the desired width of the display mode, '600' should be the height, and '16' should be the color depth.

Example

 

Imports DxVBLib

Public Class frmMain

  Dim dx As New DirectX7

  Dim dd As DirectDraw7

  Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

    Me.Show()

    dd = dx.DirectDrawCreate("")

    dim Height as Integer

    dim Width as Integer

    dim Depth as Integer

    Height=600 ' Change this to the correct number

    Width=800 ' Change this to the correct number

    Depth=16 ' Change this to the correct number

    dd.SetDisplayMode(Height, Width, Depth, 0, CONST_DDSDMFLAGS.DDSDM_DEFAULT)

  End Sub

End Class

Answer 2

Thanks for the suggestion.  As it happened, I was just rummaging around some more and found the ChangeDisplaySettings call; it only works on the default display adapter unlike ChangeDisplaySettingsEx, but that's all I need for this app.  So far as I can tell, the problem was somewhere in the three null arguments I was trying to set (based on help files for C++ usage, which was all I could find for the API), and in converting from the "As Any" which is no longer allowed in a Declare statement.

Answer 3

Hi Robinjam,

                      I have tried this code with my system , But, Its shows the exception like

NotImplementedException was unhandled by user code on CONST_DDSDMFLAGS.DDSDM_DEFAULT

And, Please tell me, what sholud i do for this error.

Sujatha.

 

 

 

Answer 4

Sorry, I don't know what went wrong. Try just replacing CONST_DDSDMFLAGS.DDSDM_DEFAULT with 0.

Answer 5

Hey,

Actually, I have did a mistake, Now its works fine.

Thanks for the help and reply.

Nice to meet you.

Regards,

Sujatha.

 

 

 

Answer 6

You complete noob

Actually upon reflection that was totally uncalled for. You aren't a noob at all.

Answer 7

Although the DirectX method involves simpler coding, there is a caveat to using this method: You are only able to change to display modes which DirectX recognizes and not necessarily to any of the modes which your display adapter might support.

For example, on my system I am only able to change BitDepth to 16 or 32 bits. Nothing lower. If I want to change to 256-color mode I cannot do it with DirectX.

(refer to http://msdn.microsoft.com/archive/default.asp?url=/archive/en-us/directx9_m_Summer_04/directx/direct3d/gettingstarted/direct3dsurfaces/surfaceformats.asp for details about supported formats).

I'm really not too familiar with the DirectDraw API, so if someone knows a way to enumerate and change to all the adapters supported modes, please post.

FYI, I'm working on wrapping the API functions into a VB.Net (2005) class which can be dropped into an app or used via DLL. I'll post back when it is finished for anyone who might be interested.

Cheers,

Dean

Answer 8

Thanks for this excellent code

 

It worked!!!

 

// PCM2 and bevin

Answer 9

i found a problem with the return resolution, i changed from 1024 x 768 to 800 x 600.

when the program exited, it put the resolution back to 1024 x 768 however the working desktop was actually fixed in the res of 800 x 600. people will only find this error if they shrink to a lower res.

if they put this in an exit code it will fix the problem and the user will have full control of the desktop:

dd.RestoreDisplayMode()

 

 

 

Answer 10

here's a working api way:

Code Block

Imports System.Runtime.InteropServices

' see msdn on "Changing Screen Orientation Programmatically" for tablet pc.
' note: I couldn't change orientation on xp, or find anyone claiming they could!
' http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dntablet/html/tbconChgScrn.asp


<StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Ansi)> _
Friend Structure DEVMODE

    <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=32)> _
    Public dmDeviceName As String
    Public dmSpecVersion As Short
    Public dmDriverVersion As Short
    Public dmSize As Short
    Public dmDriverExtra As Short
    Public dmFields As Integer
    Public dmPositionX As Integer
    Public dmPositionY As Integer
    Public dmDisplayOrientation As Integer
    Public dmDisplayFixedOutput As Integer
    Public dmColor As Short
    Public dmDuplex As Short
    Public dmYResolution As Short
    Public dmTTOption As Short
    Public dmCollate As Short
    <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=32)> _
    Public dmFormName As String
    Public dmLogPixels As Short
    Public dmBitsPerPel As Short
    Public dmPelsWidth As Integer
    Public dmPelsHeight As Integer
    Public dmDisplayFlags As Integer
    Public dmDisplayFrequency As Integer
    Public dmICMMethod As Integer
    Public dmICMIntent As Integer
    Public dmMediaType As Integer
    Public dmDitherType As Integer
    Public dmReserved1 As Integer
    Public dmReserved2 As Integer
    Public dmPanningWidth As Integer
    Public dmPanningHeight As Integer
End Structure

Friend Class NativeMethods

    ' PInvoke declaration for EnumDisplaySettings Win32 API
    <DllImport("user32.dll", CharSet:=CharSet.Ansi)> _
    Public Shared Function EnumDisplaySettings( _
    ByVal lpszDeviceName As String, _
    ByVal iModeNum As Integer, _
    ByRef lpDevMode As DEVMODE) As Integer
    End Function

    ' PInvoke declaration for ChangeDisplaySettings Win32 API
    <DllImport("user32.dll", CharSet:=CharSet.Ansi)> _
    Public Shared Function ChangeDisplaySettings( _
    ByRef lpDevMode As DEVMODE, _
    ByVal dwFlags As Integer) As Integer
    End Function

End Class

Public Class ResolutionChanger

    Private Shared Function CreateDevMode() As DEVMODE
        Dim dm As New DEVMODE
        dm.dmDeviceName = New String(New Char(32) {})
        dm.dmFormName = New String(New Char(32) {})
        dm.dmSize = CShort(Marshal.SizeOf(dm))
        Return dm
    End Function

    Public Enum DisplayChangeResultCode
        DISP_CHANGE_SUCCESSFUL = 0
        DISP_CHANGE_RESTART = 1
        DISP_CHANGE_FAILED = -1
        DISP_CHANGE_BADMODE = -2
        DISP_CHANGE_NOTUPDATED = -3
        DISP_CHANGE_BADFLAGS = -4
        DISP_CHANGE_BADPARAM = -5
        DISP_CHANGE_BADDUALVIEW = -6
    End Enum

    Public Shared Sub ChangeResolution(ByVal width As Integer, ByVal height As Integer, ByVal freq As Integer)

        Const DM_PELSWIDTH As Integer = &H80000
        Const DM_PELSHEIGHT As Integer = &H100000
        Const DM_DISPLAYFREQUENCY As Integer = &H400000
        Const ENUM_CURRENT_SETTINGS As Integer = -1
        Dim DevM As DEVMODE = CreateDevMode()
        Dim enumResult As Integer
        Dim changeResult As DisplayChangeResultCode

        DevM.dmFields = DM_PELSWIDTH Or DM_PELSHEIGHT Or DM_DISPLAYFREQUENCY

        enumResult = NativeMethods.EnumDisplaySettings(Nothing, ENUM_CURRENT_SETTINGS, DevM)

        DevM.dmPelsWidth = width
        DevM.dmPelsHeight = height
        DevM.dmDisplayFrequency = freq

        changeResult = CType(NativeMethods.ChangeDisplaySettings(DevM, 0), DisplayChangeResultCode)

        If changeResult <> DisplayChangeResultCode.DISP_CHANGE_SUCCESSFUL Then
            Throw New Exception("Failed to change resolution: " & changeResult.ToString)
        End If

    End Sub

End Class

 

see also :

http://cid-862dee3ec267cb5c.skydrive.live.com/self.aspx/Public/DisplaySettings.zip

Answer 11

Hi,

It seems like the initial poster figured out how to change the user's display using the API. I tried the DirectX and even though the code is well documented and explained, it doesn't work on my XP platform.

I was wondering if anyone has been able to get this to function with Visual Basic Express 2005. I have been tasked to accomplish this in VB Express and I just cannot find a work-able solution.  Any assistance would be helpful.

Thanks!

Christine

 

Answer 12

I'm not entirely sure what the problem is. The code I wrote using DirectX was written in VB Express 2005 (I can't afford the full version ). It should work with any video card supported by DirectX. Could you explain in more detail what the problem is?

Answer 13

And sorry it took me so long to reply...

Answer 14

It's no problem at all. I wanted to do something different anyway. :)

Answer 15

 

You can also use the powerfull builtin computer.screen:

 

Dim width, height As Double

Dim widescreen as integer = 0

width = 1.0

height = 1.0

If My.Computer.Screen.Bounds.Width >= 1280 Then

widescreen = 1

width = 1.25!

End If

If My.Computer.Screen.Bounds.Height >= 1024 Then

widescreen = 1

height = 1.25!

End If

If widescreen = 1 Then

Me.Scale(New System.Drawing.SizeF(width, height))

End If

(You can check the height and weight of the current resolution and then change it to the correct resolution)

 

Answer 16

 

 hi jo0ls,

I am interested in your code. But not sure how to use it any suggestions on how to get to the mode changing commands. I'll continue to test it (no errors) on execution but nothing seems to be happening.....

Answer 17

jbassmanp,

If you were referring to the DirectDraw method of changing the display resolution, please make sure that:

1. You have at least version 7 of DirectX
2. You have added a reference to DirectX in your project
3. Your video card supports the resolution you provided

Otherwise your app will not work, and it may not even return an error at all.

Answer 18

jo0ls wrote:

here's a working api way: Imports System.Runtime.InteropServices   ' see msdn on "Changing Screen Orientation Programmatically" for tablet pc. ' note: I couldn't change orientation on xp, or find anyone claiming they could! ' http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dntablet/html/tbconChgScrn.asp     <StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Ansi)> _ Friend Structure DEVMODE       <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=32)> _     Public dmDeviceName As String     Public dmSpecVersion As Short     Public dmDriverVersion As Short     Public dmSize As Short     Public dmDriverExtra As Short     Public dmFields As Integer     Public dmPositionX As Integer     Public dmPositionY As Integer     Public dmDisplayOrientation As Integer     Public dmDisplayFixedOutput As Integer     Public dmColor As Short     Public dmDuplex As Short     Public dmYResolution As Short     Public dmTTOption As Short     Public dmCollate As Short     <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=32)> _     Public dmFormName As String     Public dmLogPixels As Short     Public dmBitsPerPel As Short     Public dmPelsWidth As Integer     Public dmPelsHeight As Integer     Public dmDisplayFlags As Integer     Public dmDisplayFrequency As Integer     Public dmICMMethod As Integer     Public dmICMIntent As Integer     Public dmMediaType As Integer     Public dmDitherType As Integer     Public dmReserved1 As Integer     Public dmReserved2 As Integer     Public dmPanningWidth As Integer     Public dmPanningHeight As Integer End Structure   Friend Class NativeMethods       ' PInvoke declaration for EnumDisplaySettings Win32 API     <DllImport("user32.dll", CharSet:=CharSet.Ansi)> _     Public Shared Function EnumDisplaySettings( _     ByVal lpszDeviceName As String, _     ByVal iModeNum As Integer, _     ByRef lpDevMode As DEVMODE) As Integer     End Function       ' PInvoke declaration for ChangeDisplaySettings Win32 API     <DllImport("user32.dll", CharSet:=CharSet.Ansi)> _     Public Shared Function ChangeDisplaySettings( _     ByRef lpDevMode As DEVMODE, _     ByVal dwFlags As Integer) As Integer     End Function   End Class   Public Class ResolutionChanger       Private Shared Function CreateDevMode() As DEVMODE         Dim dm As New DEVMODE         dm.dmDeviceName = New String(New Char(32) {})         dm.dmFormName = New String(New Char(32) {})         dm.dmSize = CShort(Marshal.SizeOf(dm))         Return dm     End Function       Public Enum DisplayChangeResultCode         DISP_CHANGE_SUCCESSFUL = 0         DISP_CHANGE_RESTART = 1         DISP_CHANGE_FAILED = -1         DISP_CHANGE_BADMODE = -2         DISP_CHANGE_NOTUPDATED = -3         DISP_CHANGE_BADFLAGS = -4         DISP_CHANGE_BADPARAM = -5         DISP_CHANGE_BADDUALVIEW = -6     End Enum       Public Shared Sub ChangeResolution(ByVal width As Integer, ByVal height As Integer, ByVal freq As Integer)           Const DM_PELSWIDTH As Integer = &H80000         Const DM_PELSHEIGHT As Integer = &H100000         Const DM_DISPLAYFREQUENCY As Integer = &H400000         Const ENUM_CURRENT_SETTINGS As Integer = -1         Dim DevM As DEVMODE = CreateDevMode()         Dim enumResult As Integer         Dim changeResult As DisplayChangeResultCode           DevM.dmFields = DM_PELSWIDTH Or DM_PELSHEIGHT Or DM_DISPLAYFREQUENCY           enumResult = NativeMethods.EnumDisplaySettings(Nothing, ENUM_CURRENT_SETTINGS, DevM)           DevM.dmPelsWidth = width         DevM.dmPelsHeight = height         DevM.dmDisplayFrequency = freq           changeResult = CType(NativeMethods.ChangeDisplaySettings(DevM, 0), DisplayChangeResultCode)           If changeResult <> DisplayChangeResultCode.DISP_CHANGE_SUCCESSFUL Then             Throw New Exception("Failed to change resolution: " & changeResult.ToString)         End If       End Sub   End Class How to you use this. I've been testing this what controls or settings textboxes etc do you use here. What do you veiw and how do you do it one example is all I need.

Answer 19

Bonjour,

Dommage que c'est en anglais !!

Merci

Answer 20

Oui!

Mais je parle un peut de Francais. Si vous voulez, je peux traduire.

Answer 21

Hi, I have read with interest your question and answer.   This is something i've been looking for for ages.   Can someone tell me if this will work in the vba environment.    I construct a lot of Access databases and every one uses their own screen res.   It would be great if I could set the res to 1024 x 768 and then reset back to the users res on exit.    Thanks in anticipation.

Answer 22

 

i found a problem with the return resolution, i changed from 1024 x 768 to 800 x 600.

when the program exited, it put the resolution back to 1024 x 768 however the working desktop was actually fixed in the res of 800 x 600. people will only find this error if they shrink to a lower res.

 

If you put this in an exit code it will fix the problem and the resolution returned correctly:

 

dd.RestoreDisplayMode()

 

Depending on which way you change res

Answer 23

i am incredulated that nobody has had any problems with their compiler processing lines such as:

 

'Const DM_PELSWIDTH As Integer = &H80000'

 

since when were integers able to exceed 4 hex digits?

Answer 24

Since VB7

 

VB.Net Long 64 bit digit.

VB6 Long 32 bit digit.

 

VB.Net: Integer 32bit digit.

VB6: Integer 16 bit dgit.

 

VB.Net: Short 16 bit digit.

?

 

Console.WriteLine(Integer.MaxValue.ToString("X"))
Console.WriteLine(UInteger.MaxValue.ToString("X"))

 

Output:

7FFFFFFF

FFFFFFFF

 

Most of these constants are DWORDS though, so to be fussy you should declare them as UInteger and add UI to the end. Then you can declare the ones that are larger than &H7FFFFFFF. But UInteger didn't exist in earlier versions of the framework.

 

Const DM_PELSWIDTH As UInteger = &H80000UI

 

 

Answer 25

I find it best to use the int plus the bit representation, e.g. Int32.  Integers have always represented the native size on a platform.  On 64 bit systems integers are now 64 bits.

Answer 26

Integer is still 32 bits, IntPtr changed (obviously, otherwise they couldn't point to all that lovely new memory).

 

imports system.runtime.interopservices

imports system.evironment

 

Console.WriteLine(GetEnvironmentVariable("PROCESSOR_ARCHITECTURE"))
Console.WriteLine(Marshal.SizeOf(GetType(Integer)))
Console.WriteLine(Marshal.SizeOf(GetType(IntPtr)))
Console.WriteLine(Marshal.SizeOf(GetType(Int32)))
Console.WriteLine(Marshal.SizeOf(GetType(Int64)))
Console.WriteLine(Marshal.SizeOf(GetType(Boolean)))

 

Vista 64:

 

AMD64
4
8
4
8
4

 

XP 32 on virtual PC:

 

x86
4
4
4
8
4

Answer 27

Can anyone please tell me if I need to install the DirectX SDK in order for the solution above to work?

I can not add a COM reference to DirectX 7, there is no listing for a DirectX COM in the list... I am running VS 2005.

 

Any help would be a fantastic!

Thanks

Answer 28

The one I posted just uses api calls not directX.

 

To use it, paste it into a new class file in your project. Then you can call the method...

 

 

Code Block

Public Class Form1

    Private Sub Form1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Click
        ResolutionChanger.ChangeResolution(800, 600, 60)
    End Sub

End Class

 

 

 

 

You can enumerate the available resolutions too.

http://www.xtremevbtalk.com/showthread.php?t=291833

 

 

Answer 29

ResolutionChanger.ChangeResolution(800, 600, 60) 
That changed the Desktop res,
but how do we return it to default state on form unload or program exit?

EDIT: Well nevermind, I figured it out
Thanks, Dato

Answer 30

Dude you are amazing, what a fantastic API script.

Thank you soooo much for replying and for taking the time to write a script like this.

 

It works fine and sets my resolution to the desired settings, but I have two questions if I may...

 

1) As asked above, how do we find the curent setting and return to this resolution after the application has closed?

2) Do you know of any .NET methods for getting the same functionality?

 

Thank you once again

Kind regards

 

Answer 31

Well here is how I did it

Code Block

'Set the Screen Res Variables

    Public HorSize As Integer
    Public VertSize As Integer

'Call these up before Changing resolution
'This Gets the Computers current Resolution
        HorSize = My.Computer.Screen.Bounds.Width
        VertSize = My.Computer.Screen.Bounds.Height      
       
'Then to reset to default you can use it like this

Private Sub Form1_Disposed(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Disposed
        ResolutionChanger.ChangeResolution(HorSize, VertSize, 60)
End Sub

Answer 32

Awsome, thanks!

 

Now all we need is a .NET version of this code..... plz someone

 

Thank you all

 

Answer 33

Er it is .Net. I think I know what you meant though. There isn't a way built into the framework to do it. It's bad practice to go around changing user settings without good reason, and the display settings are definately a user setting.

Here's a slightly extended version, I'm trying out my Windows Live Skydrive thing for the first time...

http://cid-862dee3ec267cb5c.skydrive.live.com/self.aspx/Public/DisplaySettings.zip

I noticed there is ChangeDisplaySettingsEx, which offers more options. I'll play with that some other time.

I've not tested changing any screen but the primary, it might not work at the moment.

Answer 34

robinjam wrote:

Just forget trying to use the API to change the display mode. Instead: 1. Add a COM reference to 'DirectX 7 for Visual Basic Type library' ...

How do i "add a COM" ???

It gives me these errors:

Warning    1    Namespace or type specified in the Imports 'DxVBLib' doesn't contain any public member or cannot be found. Make sure the namespace or the type is defined and contains at least one public member. Make sure the imported element name doesn't use any aliases.    C:\Users\Diogo\Documents\Visual Studio 2005\Projects\VB\DefinicoesDesistema\DefinicoesDesistema\Form2.vb    1    9    DefinicoesDesistema

Error    2    Type 'DirectX7' is not defined.    C:\Users\Diogo\Documents\Visual Studio 2005\Projects\VB\DefinicoesDesistema\DefinicoesDesistema\Form2.vb    5    19    DefinicoesDesistema

Error    3    Type 'DirectDraw7' is not defined.    C:\Users\Diogo\Documents\Visual Studio 2005\Projects\VB\DefinicoesDesistema\DefinicoesDesistema\Form2.vb    7    15    DefinicoesDesistema

Error    4    Name 'CONST_DDSDMFLAGS' is not declared.    C:\Users\Diogo\Documents\Visual Studio 2005\Projects\VB\DefinicoesDesistema\DefinicoesDesistema\Form2.vb    27    52    DefinicoesDesistema


Thanks

Answer 35

Now i know how to add a com reference, but in the COM list, there isn't any 'DirectX 7 for Visual Basic Type library'

Anyone helps?

Answer 36

Install the DirectX SDK or search for dx7vb.dll, but check this thread:   http://forums.microsoft.com/msdn/showpost.aspx?postid=1223939&siteid=1&sb=0&d=1&at=7&ft=11&tf=0&pageid=3

 

Answer 37

I installed Microsoft directx sdk (march 2008)

The code for this version should have something different, because it still gives me errors... It works with directx 9, isn't it? Can anyone please change the code to this version?

Thanks

Answer 38

'Put the following code in a module, and you will get a function SetResolution ready to work!

Imports System.Runtime.InteropServices

Private Declare Auto Function EnumDisplaySettings Lib "user32.dll" ( _
    <MarshalAs(UnmanagedType.LPTStr)> ByVal lpszDeviceName As String, _
    ByVal iModeNum As Int32, _
    ByRef lpDevMode As DEVMODE _
) As Boolean

Private Declare Auto Function ChangeDisplaySettings Lib "user32.dll" ( _
    ByRef lpDevMode As DEVMODE, _
    ByVal dwFlags As Int32 _
) As Int32

Private Const DM_BITSPERPEL As Int32 = &H40000
Private Const DM_PELSWIDTH As Int32 = &H80000
Private Const DM_PELSHEIGHT As Int32 = &H100000

Private Const DISP_CHANGE_SUCCESSFUL As Int32 = 0

<StructLayout(LayoutKind.Sequential)> _
Private Structure POINTL
    Public x As Int32
    Public y As Int32
End Structure

<StructLayout(LayoutKind.Explicit)> _
Private Structure DEVMODE_union1
    ' struct {
        <FieldOffset(0)> Public dmOrientation As Int16
        <FieldOffset(2)> Public dmPaperSize As Int16
        <FieldOffset(4)> Public dmPaperLength As Int16
        <FieldOffset(6)> Public dmPaperWidth As Int16
    ' }
    <FieldOffset(0)> Public dmPosition As POINTL
End Structure

<StructLayout(LayoutKind.Explicit)> _
Private Structure DEVMODE_union2
    <FieldOffset(0)> Public dmDisplayFlags As Int32
    <FieldOffset(0)> Public dmNup As Int32
End Structure

<StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Auto)> _
Private Structure DEVMODE
    Private Const CCDEVICENAME As Int32 = 32
    Private Const CCFORMNAME As Int32 = 32

    <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=CCDEVICENAME)> _
    Public dmDeviceName As String
    Public dmSpecVersion As Int16
    Public dmDriverVersion As Int16
    Public dmSize As Int16
    Public dmDriverExtra As Int16
    Public dmFields As Int32
    Public u1 As DEVMODE_union1
    Public dmScale As Int16
    Public dmCopies As Int16
    Public dmDefaultSource As Int16
    Public dmPrintQuality As Int16
    Public dmColor As Int16
    Public dmDuplex As Int16
    Public dmYResolution As Int16
    Public dmTTOption As Int16
    Public dmCollate As Int16
    <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=CCFORMNAME)> _
    Public dmFormName As String
    Public dmUnusedPadding As Int16
    Public dmBitsPerPel As Int16
    Public dmPelsWidth As Int32
    Public dmPelsHeight As Int32
    Public u2 As DEVMODE_union2
    Public dmDisplayFrequency As Int32
    Public dmICMMethod As Int32
    Public dmICMIntent As Int32
    Public dmMediaType As Int32
    Public dmDitherType As Int32
    Public dmReserved1 As Int32
    Public dmReserved2 As Int32
    Public dmPanningWidth As Int32
    Public dmPanningHeight As Int32
End Structure

Public Function SetResolution( _
    ByVal Width As Int32, _
    ByVal Height As Int32, _
    ByVal BitsPerPixel As Int16 _
) As Boolean
    Dim dm As DEVMODE
    If Not EnumDisplaySettings(Nothing, 0, dm) Then
        Return False
    Else
        With dm
            .dmFields = _
                DM_PELSWIDTH Or DM_PELSHEIGHT Or DM_BITSPERPEL
            .dmPelsWidth = Width
            .dmPelsHeight = Height
            .dmBitsPerPel = BitsPerPixel
        End With
        Return (ChangeDisplaySettings(dm, 0) = DISP_CHANGE_SUCCESSFUL)
    End If
End Function