Multiple Display Configuration's setting change in win 8

Question

In win8, it has Multiple Display Configuration in "Second screen".
PC screen only, Duplicate, Extend and Second screen only.
My question is how to get the status changed event by WndProc messages : HwndSource in c#?

Does anyone have similar experiences?

Answer 1

Same with earlier OS, we could p/invoke the EnumDisplaySettings API to get the DEVMODE, and

• in  Extend mode, the two or multiple screens dmPosition value are different, for example, my two monitors are set as, the values are: (0,0) and (1366,-512)

Code:

  [DllImport("user32.dll")]
  public static extern int EnumDisplaySettings(string deviceName, int modeNum, ref DEVMODE devMode);

  public struct POINTL
  {
      public Int32 x;
      public Int32 y;
  }

  [StructLayout(LayoutKind.Explicit, CharSet = CharSet.Ansi)]
  public struct DEVMODE
  {
      public const int CCHDEVICENAME = 32;
      public const int CCHFORMNAME = 32;

      [MarshalAs(UnmanagedType.ByValTStr, SizeConst = CCHDEVICENAME)]
      [System.Runtime.InteropServices.FieldOffset(0)]
      public string dmDeviceName;
      [System.Runtime.InteropServices.FieldOffset(32)]
      public Int16 dmSpecVersion;
      [System.Runtime.InteropServices.FieldOffset(34)]
      public Int16 dmDriverVersion;
      [System.Runtime.InteropServices.FieldOffset(36)]
      public Int16 dmSize;
      [System.Runtime.InteropServices.FieldOffset(38)]
      public Int16 dmDriverExtra;
      [System.Runtime.InteropServices.FieldOffset(40)]
      public DM dmFields;

      [System.Runtime.InteropServices.FieldOffset(44)]
      Int16 dmOrientation;
      [System.Runtime.InteropServices.FieldOffset(46)]
      Int16 dmPaperSize;
      [System.Runtime.InteropServices.FieldOffset(48)]
      Int16 dmPaperLength;
      [System.Runtime.InteropServices.FieldOffset(50)]
      Int16 dmPaperWidth;
      [System.Runtime.InteropServices.FieldOffset(52)]
      Int16 dmScale;
      [System.Runtime.InteropServices.FieldOffset(54)]
      Int16 dmCopies;
      [System.Runtime.InteropServices.FieldOffset(56)]
      Int16 dmDefaultSource;
      [System.Runtime.InteropServices.FieldOffset(58)]
      Int16 dmPrintQuality;

      [System.Runtime.InteropServices.FieldOffset(44)]
      public POINTL dmPosition;
      [System.Runtime.InteropServices.FieldOffset(52)]
      public Int32 dmDisplayOrientation;
      [System.Runtime.InteropServices.FieldOffset(56)]
      public Int32 dmDisplayFixedOutput;

      [System.Runtime.InteropServices.FieldOffset(60)]
      public short dmColor;
      [System.Runtime.InteropServices.FieldOffset(62)]
      public short dmDuplex;
      [System.Runtime.InteropServices.FieldOffset(64)]
      public short dmYResolution;
      [System.Runtime.InteropServices.FieldOffset(66)]
      public short dmTTOption;
      [System.Runtime.InteropServices.FieldOffset(68)]
      public short dmCollate;
      [System.Runtime.InteropServices.FieldOffset(72)]
      [MarshalAs(UnmanagedType.ByValTStr, SizeConst = CCHFORMNAME)]
      public string dmFormName;
      [System.Runtime.InteropServices.FieldOffset(102)]
      public Int16 dmLogPixels;
      [System.Runtime.InteropServices.FieldOffset(104)]
      public Int32 dmBitsPerPel;
      [System.Runtime.InteropServices.FieldOffset(108)]
      public Int32 dmPelsWidth;
      [System.Runtime.InteropServices.FieldOffset(112)]
      public Int32 dmPelsHeight;
      [System.Runtime.InteropServices.FieldOffset(116)]
      public Int32 dmDisplayFlags;
      [System.Runtime.InteropServices.FieldOffset(116)]
      public Int32 dmNup;
      [System.Runtime.InteropServices.FieldOffset(120)]
      public Int32 dmDisplayFrequency;
  }
  [Flags()]
  public enum DM : int
  {
      Orientation = 0x1,
      PaperSize = 0x2,
      PaperLength = 0x4,
      PaperWidth = 0x8,
      Scale = 0x10,
      Position = 0x20,
      NUP = 0x40,
      DisplayOrientation = 0x80,
      Copies = 0x100,
      DefaultSource = 0x200,
      PrintQuality = 0x400,
      Color = 0x800,
      Duplex = 0x1000,
      YResolution = 0x2000,
      TTOption = 0x4000,
      Collate = 0x8000,
      FormName = 0x10000,
      LogPixels = 0x20000,
      BitsPerPixel = 0x40000,
      PelsWidth = 0x80000,
      PelsHeight = 0x100000,
      DisplayFlags = 0x200000,
      DisplayFrequency = 0x400000,
      ICMMethod = 0x800000,
      ICMIntent = 0x1000000,
      MediaType = 0x2000000,
      DitherType = 0x4000000,
      PanningWidth = 0x8000000,
      PanningHeight = 0x10000000,
      DisplayFixedOutput = 0x20000000
  }
  public const int ENUM_CURRENT_SETTINGS = -1;
  
  ......
  foreach (Screen screen in Screen.AllScreens)
  {

      DEVMODE dm = new DEVMODE();
      dm.dmDeviceName = new String(new char[32]);
      dm.dmFormName = new String(new char[32]);
      dm.dmSize = (short)Marshal.SizeOf(dm);

      EnumDisplaySettings(screen.DeviceName, ENUM_CURRENT_SETTINGS, ref dm);
      POINTL position = (POINTL)dm.dmPosition;
      Console.WriteLine("{0}, position is : ({1},{2})", screen.DeviceName, position.x, position.y);
  }        
  ......

• if it is show only in one screen or duplicate, there is only one Screen instance in the Screen.AllScreens

---

Bob Bao [MSFT]
MSDN Community Support | Feedback to us

Answer 2

Thanks for Bob's reply.

I think I found the answer.
WM_DISPLAYCHANGE : 0x7e
http://msdn.microsoft.com/en-us/library/windows/desktop/dd145210(v=vs.85).aspx