实现双屏显示-从主显示器分离所有辅助显示设备

症状

当您在 Microsoft Windows 95、 Windows 98、 Windows 98 第二版或 Windows Millennium 版 (Me)...

 

DEVMODE 结构中您需要设置为零将 dmFields 中调用 ChangeDisplaySettingsEx 之前下列标志的 DEVMODE 条目：

DM_PELSWIDTH
DM_PELSHEIGHT
DM_BITSPERPEL
DM_POSITION
DM_DISPLAYFREQUENCY
DM_DISPLAYFLAGS

注： 您应该通过调用 EnumDisplaySettings，以便您可以返回到桌面附加显示器，使用另一个调用 ChangeDisplaySettingsEx 保存当前的 DEVMODE。

下面的代码演示如何分离所有辅助显示设备从桌面：

void DetachDisplay()
{
    BOOL            FoundSecondaryDisp = FALSE;
    DWORD           DispNum = 0;
    DISPLAY_DEVICE  DisplayDevice;
    LONG            Result;
    TCHAR           szTemp[200];
    int             i = 0;
    DEVMODE   defaultMode;

    // initialize DisplayDevice
    ZeroMemory(&DisplayDevice, sizeof(DisplayDevice));
    DisplayDevice.cb = sizeof(DisplayDevice);

    // get all display devices
    while (EnumDisplayDevices(NULL, DispNum, &DisplayDevice, 0))
        {
        ZeroMemory(&defaultMode, sizeof(DEVMODE));
        defaultMode.dmSize = sizeof(DEVMODE);
        if ( !EnumDisplaySettings((LPSTR)DisplayDevice.DeviceName, ENUM_REGISTRY_SETTINGS, &defaultMode) )
                  OutputDebugString("Store default failed/n");

        if ((DisplayDevice.StateFlags & DISPLAY_DEVICE_ATTACHED_TO_DESKTOP) &&
            !(DisplayDevice.StateFlags & DISPLAY_DEVICE_PRIMARY_DEVICE))
            {
            DEVMODE    DevMode;
            ZeroMemory(&DevMode, sizeof(DevMode));
            DevMode.dmSize = sizeof(DevMode);
            DevMode.dmFields = DM_PELSWIDTH | DM_PELSHEIGHT | DM_BITSPERPEL | DM_POSITION
                        | DM_DISPLAYFREQUENCY | DM_DISPLAYFLAGS ;
            Result = ChangeDisplaySettingsEx((LPSTR)DisplayDevice.DeviceName, &DevMode, NULL, CDS_UPDATEREGISTRY, NULL);
            Result = ChangeDisplaySettingsEx((LPSTR)DisplayDevice.DeviceName, &DevMode, NULL, CDS_UPDATEREGISTRY, NULL);

            //The code below shows how to re-attach the secondary displays to the desktop

            //ChangeDisplaySettingsEx((LPSTR)DisplayDevice.DeviceName, &defaultMode, NULL, CDS_UPDATEREGISTRY, NULL);
            //ChangeDisplaySettingsEx((LPSTR)DisplayDevice.DeviceName, &defaultMode, NULL, CDS_UPDATEREGISTRY, NULL);
           
            }

        // Reinit DisplayDevice just to be extra clean

        ZeroMemory(&DisplayDevice, sizeof(DisplayDevice));
        DisplayDevice.cb = sizeof(DisplayDevice);
        DispNum++;
        } // end while for all display devices
}