static extern DISP_CHANGE ChangeDisplaySettingsEx(string lpszDeviceName, ref DEVMODE lpDevMode, IntPtr hwnd, ChangeDisplaySettingsFlags dwflags, IntPtr lParam);

Private Shared Function ChangeDisplaySettingsEx(ByVal lpszDeviceName As String, ByRef lpDevMode As DEVMODE, ByVal hwnd As IntPtr, ByVal dwflags As UInteger, ByVal lParam As IntPtr) As DISP_CHANGE

ChangeDisplaySettingsEx(d.DeviceName, ref dm, IntPtr.Zero, CDS_UPDATEREGISTRY, IntPtr.Zero);

static extern int ChangeDisplaySettingsEx(string lpszDeviceName, ref DEVMODE lpDevMode, IntPtr hwnd, int dwflags, IntPtr lParam);

Declare Function ChangeDisplaySettingsEx Lib "coredll.dll" (ByVal lpszDeviceName As String, ByVal lpDevMode As Byte(), ByVal hwnd As IntPtr, ByVal dwflags As CDSFlags, ByVal lParam As IntPtr) As CDSRet

    static extern int ChangeDisplaySettingsEx(string lpszDeviceName,

        ChangeDisplaySettingsEx(null, ref DevM2, IntPtr.Zero, 2, IntPtr.Zero); // 2 = test

        ChangeDisplaySettingsEx(null, ref devmode, IntPtr.Zero, 2, IntPtr.Zero); // 2 = test

        ChangeDisplaySettingsEx(null, ref devmode, IntPtr.Zero, 0, IntPtr.Zero); // 0 = set

    Friend Shared Function ChangeDisplaySettingsEx(ByVal lpszDeviceName As String, ByVal lpDevMode As Byte(), ByVal hwnd As IntPtr, ByVal dwflags As CDSFlags, ByVal lParam As IntPtr) As CDSRet

        Dim ret As CDSRet = ChangeDisplaySettingsEx(Nothing, devMode.Data, IntPtr.Zero, 0, IntPtr.Zero)

Used with ChangeDisplaySettings and ChangeDisplaySettingsEx