How to adjust monitor orientation in Windows 7?

Question

I want to write some funny code to flip upside down in Windows 7. See screenshot of the option I want to control.

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Here is the code I have:

class Program { public const long WM_PAINT=0x0F; public const long WM_DISPLAYCHANGE=0x7E; [StructLayout(LayoutKind.Sequential, CharSet=CharSet.Auto)] public struct DEVMODE // taken from Win API { ... public System.Windows.Forms.ScreenOrientation dmDisplayOrientation; } [DllImport("user32.dll", CharSet=CharSet.Auto)] public static extern bool EnumDisplaySettings(string lpszDeviceName, int iModeNum, ref DEVMODE lpDevMode); [DllImport("user32.dll", CharSet=CharSet.Ansi)] public static extern int ChangeDisplaySettings(ref DEVMODE lpDevMode, int dwFlags); [DllImport("User32.Dll")] public static extern long PostMessage(IntPtr hWnd, long wMsg, long wParam, long lParam); static void Main(string[] args) { ScreenOrientation ori=ScreenOrientation.Angle0; DEVMODE mode=new DEVMODE() { dmSize=(short)Marshal.SizeOf(typeof(DEVMODE)), dmDriverExtra=0, dmDeviceName=new string(new char[32]), dmFormName=new string(new char[32]), }; try { EnumDisplaySettings(null, -1, ref mode); if((mode.dmFields&0x80)>0) { ori=mode.dmDisplayOrientation; } mode.dmDisplayOrientation=ScreenOrientation.Angle270; int temp=mode.dmPelsWidth; mode.dmPelsWidth=mode.dmPelsHeight; mode.dmPelsHeight=temp; int ret=ChangeDisplaySettings(ref mode, 0); PostMessage(Process.GetCurrentProcess().Handle, WM_DISPLAYCHANGE, 0, 0); ... } catch { } } } 

which starts, but does not produce any affects.

Link code: http://justlikeamagic.com/2009/05/21/changing-display-settings-programmatically/ and http://msdn.microsoft.com/en-us/library/ms812499.aspx#tbconchgscrn_chngingdisplay

Answer 1

I came up with something.

Please see: MultiMonitorHelper

It includes the necessary structures for Win7 so that you can call SetDisplayConfig and other functions.

Actual example of how to rotate the monitor 90 degrees:

  int numPathArrayElements; int numModeInfoArrayElements; const QueryDisplayFlags pathType = QueryDisplayFlags.OnlyActivePaths; // query active paths from the current computer. // note that 0 is equal to SUCCESS! // TODO; HARDCODE MAGIC VALUES AWAY. if (CCDWrapper.GetDisplayConfigBufferSizes(pathType, out numPathArrayElements, out numModeInfoArrayElements) == 0) { var pathInfoArray = new DisplayConfigPathInfo[numPathArrayElements]; var modeInfoArray = new DisplayConfigModeInfo[numModeInfoArrayElements]; // TODO; FALLBACK MECHANISM THAT HANDLES DIFFERENT VALUES FOR ZERO. if (CCDWrapper.QueryDisplayConfig( pathType, ref numPathArrayElements, pathInfoArray, ref numModeInfoArrayElements, modeInfoArray, IntPtr.Zero) == 0) { pathInfoArray[0].targetInfo.rotation = DisplayConfigRotation.Rotate90; CCDWrapper.SetDisplayConfig((uint) numPathArrayElements, pathInfoArray, (uint) numModeInfoArrayElements, modeInfoArray, SdcFlags.Apply | SdcFlags.UseSuppliedDisplayConfig); } } 

it is right now, which means that there is currently no C # style API, but you can use these structures nonetheless.

Answer 2

In Windows 7, ChangeDisplaySetting has a known compatibility issue. A workaround is to call the WDK function: SetDisplayConfig .

http://social.msdn.microsoft.com/Forums/en/windowsuidevelopment/thread/5bc2396d-1e0e-44fb-b73b-95f8dfc45684