Question

我正在尝试创建一个显示所有显示和监视器名称的函数。但是第二次调用enumDisplayDevices时，如果第一个参数是lpDisplayDevice.DeviceName，则会出错。我知道这是第一个参数因为它设置为“IntPtr.Zero”而不是错误。

我找不到另一个如何在C＃中执行此操作的示例。

    public static void show_display_devices()
    {
        DISPLAY_DEVICE lpDisplayDevice = new DISPLAY_DEVICE(0);     // OUT
        int devNum = 0;
        while(true)
        {
            bool success = EnumDisplayDevices( IntPtr.Zero,  devNum,  ref lpDisplayDevice,  0);
            if( !success )
                break;

            Console.WriteLine("\ndevNum =" + devNum);
            Console.WriteLine("cb =" + lpDisplayDevice.cb);
            Console.WriteLine("DeviceID =" + lpDisplayDevice.DeviceID);
            Console.WriteLine("DeviceKey =" + lpDisplayDevice.DeviceKey);
            Console.WriteLine("DeviceName =" + lpDisplayDevice.DeviceName.Trim());
            Console.WriteLine("DeviceString =" + lpDisplayDevice.DeviceString.Trim());
            // Show monitor name:
            DISPLAY_DEVICE monitor_name = new DISPLAY_DEVICE(0);        // OUT

               >>>>>>>>>>>   NEXT LINE HAS ERROR:  <<<<<<<<<<<<<<<
            EnumDisplayDevices(lpDisplayDevice.DeviceName, 0, ref monitor_name, 0);  <<<<<<<<<<<<<<<<<  "lpDisplayDevice.DeviceName" causes error  <<<<<<
                               ^^^^^^^^^^^^^^^^^^^^^^^^^^ - CAUSES ERROR <<<<<<

            Console.WriteLine("Monitor name =" + lpDisplayDevice.DeviceString.Trim());

            ++devNum;
        }
    }

Answer 1

问题在于声明“private static extern bool EnumDisplayDevices（）”。我将lpDevice从IntPtr更改为string，它对我有用。

下面的源代码在“输出”窗口中生成以下内容：

devNum = 0 cb = 424 DeviceID = PCI \ VEN_10DE＆amp; DEV_0402＆amp; SUBSYS_0440196E＆amp; REV_A1 DeviceKey = \ Registry \ Machine \ System \ CurrentControlSet \ Control \ Video {B757E378-AF2E-4826-BA9E-927C5B81B139} \ 0000 DeviceName = \。\ DISPLAY1 DeviceString = NVIDIA GeForce 8600 GT 线程'RunPowerStatusMonitor Thread'（0x2108）已退出，代码为0（0x0）。 Monitor name = Generic PnP Monitor

devNum = 1 cb = 424 DeviceID = PCI \ VEN_10DE＆amp; DEV_0402＆amp; SUBSYS_0440196E＆amp; REV_A1 DeviceKey = \ Registry \ Machine \ System \ CurrentControlSet \ Control \ Video {B757E378-AF2E-4826-BA9E-927C5B81B139} \ 0001 DeviceName = \。\ DISPLAY2 DeviceString = NVIDIA GeForce 8600 GT Monitor name = Generic PnP Monitor

        public static void show_display_devices()
    {
        DISPLAY_DEVICE lpDisplayDevice = new DISPLAY_DEVICE(0);     // OUT
            DISPLAY_DEVICE monitor_name = new DISPLAY_DEVICE(0);        // OUT

        int devNum = 0;
        while (EnumDisplayDevices(null, devNum, ref lpDisplayDevice, 0))
        {

            Console.WriteLine("\ndevNum =" + devNum);
            Console.WriteLine("cb =" + lpDisplayDevice.cb);
            Console.WriteLine("DeviceID =" + lpDisplayDevice.DeviceID);
            Console.WriteLine("DeviceKey =" + lpDisplayDevice.DeviceKey);
            Console.WriteLine("DeviceName =" + lpDisplayDevice.DeviceName.Trim());
            Console.WriteLine("DeviceString =" + lpDisplayDevice.DeviceString.Trim());
            // Show monitor name:



            EnumDisplayDevices( lpDisplayDevice.DeviceName, 0, ref monitor_name, 0);
            Console.WriteLine("Monitor name =" + monitor_name.DeviceString.Trim());

            ++devNum;
        }
    }

    [DllImport("User32.dll")]
    private static extern bool EnumDisplayDevices(
        string lpDevice, int iDevNum,
        ref DISPLAY_DEVICE lpDisplayDevice, int dwFlags);




    [StructLayout(LayoutKind.Sequential)]
    public struct DISPLAY_DEVICE
    {
        public int cb;
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 32)]
        public string DeviceName;
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 128)]
        public string DeviceString;
        public int StateFlags;
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 128)]
        public string DeviceID;
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 128)]
        public string DeviceKey;

        public DISPLAY_DEVICE(int flags)
        {
            cb = 0;
            StateFlags = flags;
            DeviceName = new string((char)32, 32);
            DeviceString = new string((char)32, 128);
            DeviceID = new string((char)32, 128);
            DeviceKey = new string((char)32, 128);
            cb = Marshal.SizeOf(this);
        }
    }

C＃如何获取Windows监视器名称

1 个答案: