UlteriusServer.Api.Win32.SessionInfo.GetSessionLockState C# (CSharp) Method

        public static LockState GetSessionLockState(uint sessionId)
        {
            IntPtr ppBuffer;
            uint pBytesReturned;

            var result = WTSQuerySessionInformation(
                WtsCurrentServer,
                sessionId,
                WTS_INFO_CLASS.WTSSessionInfoEx,
                out ppBuffer,
                out pBytesReturned
                );

            if (result == False)
                return LockState.Unknown;

            var sessionInfoEx = Marshal.PtrToStructure<WTSINFOEX>(ppBuffer);

            if (sessionInfoEx.Level != 1)
                return LockState.Unknown;

            var lockState = sessionInfoEx.Data.WTSInfoExLevel1.SessionFlags;
            WTSFreeMemoryEx(WTS_TYPE_CLASS.WTSTypeSessionInfoLevel1, ppBuffer, pBytesReturned);

            if (IsWin7)
            {
                /* Ref: https://msdn.microsoft.com/en-us/library/windows/desktop/ee621019(v=vs.85).aspx
                    * Windows Server 2008 R2 and Windows 7:  Due to a code defect, the usage of the WTS_SESSIONSTATE_LOCK
                    * and WTS_SESSIONSTATE_UNLOCK flags is reversed. That is, WTS_SESSIONSTATE_LOCK indicates that the
                    * session is unlocked, and WTS_SESSIONSTATE_UNLOCK indicates the session is locked.
                    * */
                switch (lockState)
                {
                    case WtsSessionstateLock:
                        return LockState.Unlocked;

                    case WtsSessionstateUnlock:
                        return LockState.Locked;

                    default:
                        return LockState.Unknown;
                }
            }
            switch (lockState)
            {
                case WtsSessionstateLock:
                    return LockState.Locked;

                case WtsSessionstateUnlock:
                    return LockState.Unlocked;

                default:
                    return LockState.Unknown;
            }
        }