C# Signature:

[DllImport("user32.dll", CharSet=CharSet.Unicode))]
static extern bool EnumDisplayDevices(string lpDevice, uint iDevNum,
   ref DISPLAY_DEVICE lpDisplayDevice, uint dwFlags);

User-Defined Types:

DISPLAY_DEVICE

Notes:

None.

Tips & Tricks:

Please add some!

Sample Code:

  // This method will return the size of the complete desktop area, taking all attached devices into account.
  public Size GetDesktopSize()
  {
    Rectangle desktop = new Rectangle();

    DISPLAY_DEVICE device = new DISPLAY_DEVICE();
    device.cb = System.Runtime.InteropServices.Marshal.SizeOf(typeof(DISPLAY_DEVICE));
    device.DeviceName = new string(' ', 32);
    device.DeviceString = new string(' ', 128);
    device.DeviceKey = new string(' ', 128);
    device.DeviceID = new string(' ', 128);

    for(uint i = 0; ; i++)
    {
      if (!Win32.EnumDisplayDevices(null, i, ref device, 0))
    break;

      // If it's not connected to the desktop, then ignore it.
      if ((device.StateFlags & 1) == 0)
    continue;

      // Get the settings of the current display mode for this device.
      DEVMODE devMode = new DEVMODE();
      if (!Win32.EnumDisplaySettings(device.DeviceName, uint.MaxValue, ref devMode))
    continue;

      // This is the rectangle defined by this device
      Rectangle deviceRect = new Rectangle(devMode.dmPosition.x, devMode.dmPosition.y,
             devMode.dmPelsWidth, devMode.dmPelsHeight);

      // Update the "desktop" rectangle with the new device
      if (desktop.Left > deviceRect.Left)
    desktop.Location = new Point(deviceRect.Left, desktop.Y);
      if (desktop.Top > deviceRect.Top)
    desktop.Location = new Point(desktop.X, deviceRect.Top);
      if (desktop.Right < deviceRect.Right)
    desktop.Size = new Size(deviceRect.Width, desktop.Height);
      if (desktop.Bottom < deviceRect.Bottom)
    desktop.Size = new Size(desktop.Width, deviceRect.Height);
    }

    // And return the size of the total desktop.
    return desktop.Size;
  }

Alternative Managed API:

Do you know one? Please contribute it!