public static extern bool EnumDisplayDevices(string lpDevice, uint iDevNum, ref DISPLAY_DEVICE lpDisplayDevice, uint dwFlags);
public static bool SetAsPrimaryMonitor(Screen destinationScreen)
{
var device = new DISPLAY_DEVICE();
var deviceMode = new DEVMODE();
device.cb = Marshal.SizeOf(device);
uint id;
for (id = 0; NativeMethods.EnumDisplayDevices(null, id, ref device, 0); id++)
{
if (device.DeviceName == destinationScreen.DeviceName)
{
break;
}
}
if (device.DeviceName != destinationScreen.DeviceName)
{
Logger.Instance.LogMessage(TracingLevel.ERROR, $"EnumDisplayDevices did not return the screen: {destinationScreen.DeviceName}");
return(false);
}
NativeMethods.EnumDisplaySettings(device.DeviceName, -1, ref deviceMode);
var offsetx = deviceMode.dmPosition.x;
var offsety = deviceMode.dmPosition.y;
deviceMode.dmPosition.x = 0;
deviceMode.dmPosition.y = 0;
NativeMethods.ChangeDisplaySettingsEx(
device.DeviceName,
ref deviceMode,
(IntPtr)null,
(ChangeDisplaySettingsFlags.CDS_SET_PRIMARY | ChangeDisplaySettingsFlags.CDS_UPDATEREGISTRY | ChangeDisplaySettingsFlags.CDS_NORESET),
IntPtr.Zero);
device = new DISPLAY_DEVICE();
device.cb = Marshal.SizeOf(device);
// Update remaining devices
for (uint otherid = 0; NativeMethods.EnumDisplayDevices(null, otherid, ref device, 0); otherid++)
{
if (device.StateFlags.HasFlag(DisplayDeviceStateFlags.AttachedToDesktop) && otherid != id)
{
device.cb = Marshal.SizeOf(device);
var otherDeviceMode = new DEVMODE();
NativeMethods.EnumDisplaySettings(device.DeviceName, -1, ref otherDeviceMode);
otherDeviceMode.dmPosition.x -= offsetx;
otherDeviceMode.dmPosition.y -= offsety;
NativeMethods.ChangeDisplaySettingsEx(
device.DeviceName,
ref otherDeviceMode,
(IntPtr)null,
(ChangeDisplaySettingsFlags.CDS_UPDATEREGISTRY | ChangeDisplaySettingsFlags.CDS_NORESET),
IntPtr.Zero);
}
device.cb = Marshal.SizeOf(device);
}
// Apply settings
NativeMethods.ChangeDisplaySettingsEx(null, IntPtr.Zero, (IntPtr)null, ChangeDisplaySettingsFlags.CDS_NONE, (IntPtr)null);
return(true);
}
