WTSSendMessage弹出窗口

 private readonly IntPtr WTS_CURRENT_SERVER_HANDLE = IntPtr.Zero;

        public void ShowMessageBox(string message, string title)
        {
            List<Int32> sessions = GetActiveSessions(WTS_CURRENT_SERVER_HANDLE);
            if (sessions.Count < 1)
            {
                int err = Marshal.GetLastWin32Error();
                LogHelper.GetInstance().ErrorLog("No active sessions found: errorCode:"+ err);
            }
            else
            {
                int resp = 0;
                WTSSendMessage(
                    WTS_CURRENT_SERVER_HANDLE,
                    WTSGetActiveConsoleSessionId(),
                    title, title.Length,
                    message, message.Length,
                    0, 0, out resp, false);
            }
        }
        private List<Int32> GetActiveSessions(System.IntPtr server)
        {
            List<Int32> ret = new List<int>();
            IntPtr ppSessionInfo = IntPtr.Zero;

            Int32 count = 0;
            Int32 retval = WTSEnumerateSessions(server, 0, 1, ref ppSessionInfo, ref count);
            Int32 dataSize = Marshal.SizeOf(typeof(WTS_SESSION_INFO));

            Int64 current = (int)ppSessionInfo;

            if (retval != 0)
            {
                for (int i = 0; i < count; i++)
                {
                    WTS_SESSION_INFO si = (WTS_SESSION_INFO)Marshal.PtrToStructure((System.IntPtr)current, typeof(WTS_SESSION_INFO));
                    current += dataSize;

                    if (si.State == WTS_CONNECTSTATE_CLASS.WTSActive)
                        ret.Add(si.SessionID);
                }

                WTSFreeMemory(ppSessionInfo);
            }

            return ret;
        }

        [DllImport("wtsapi32.dll", ExactSpelling = true, SetLastError = false)]
        private static extern void WTSFreeMemory(IntPtr memory);

        [StructLayout(LayoutKind.Sequential)]
        private struct WTS_SESSION_INFO
        {
            public readonly int SessionID;
            [MarshalAs(UnmanagedType.LPStr)]
            private readonly string pWinStationName;
            public readonly WTS_CONNECTSTATE_CLASS State;
        }

        [DllImport("wtsapi32.dll", SetLastError = true)]
        static extern int WTSEnumerateSessions(
                    System.IntPtr hServer,
                    int Reserved,
                    int Version,
                    ref System.IntPtr ppSessionInfo,
                    ref int pCount);

        public enum WTS_CONNECTSTATE_CLASS
        {
            WTSActive,
            WTSConnected,
            WTSConnectQuery,
            WTSShadow,
            WTSDisconnected,
            WTSIdle,
            WTSListen,
            WTSReset,
            WTSDown,
            WTSInit
        }

        [DllImport("wtsapi32.dll", SetLastError = true)]
        private static extern bool WTSSendMessage(
            IntPtr hServer,
            int SessionId,
            String pTitle,
            int TitleLength,
            String pMessage,
            int MessageLength,
            int Style,
            int Timeout,
            out int pResponse,
            bool bWait);