protected bool Poll(int microSeconds, SelectMode mode)
        {
            fd_set readFDs = null;
            fd_set writeFDs = null;

            if (mode == SelectMode.SelectRead)
            {
                readFDs = new fd_set();
                readFDs.FD_ZERO();
                readFDs.FD_SET(mSocket);
            }
            if (mode == SelectMode.SelectWrite)
            {
                writeFDs = new fd_set();
                writeFDs.FD_ZERO();
                writeFDs.FD_SET(mSocket);
            }

            Int32 ret = select(0, readFDs, null, null, null);

            //Console.WriteLine("select returned: {0}", ret);

            if (readFDs.FD_ISSET(mSocket))
            {
                return true;
            }
            return false;
        }

 internal override bool Poll(int microseconds, SelectMode mode)
 {
     if (this.acceptedSock == null)
     {
         throw new IOException("Not accepted yet");
     }
     return this.acceptedSock.Poll(microseconds, mode);
 }

        public void AddCallback(SelectMode mode, Socket socket, Action<Socket> callback)
        {
            _selectable.AddCallback(mode, socket, callback);

            // If we have changed the selectable sockets interup the select to wait on the new sockets.
            if (socket != _reader)
                InterruptSelect();
        }

	public static void PreferencesGUI () {

		// Load the preferences
		if (!prefsLoaded) {
			LoadPrefs();
			prefsLoaded = true;
			OnWindowResize();
		}
		
		settingsScroll = EditorGUILayout.BeginScrollView(settingsScroll, GUILayout.MaxHeight(136));
		// Geometry Settings
		GUILayout.Label("Geometry Editing Settings", EditorStyles.boldLabel);

		_selectMode = (SelectMode)EditorGUILayout.EnumPopup("Default Selection Mode", _selectMode);
		
		_faceColor = EditorGUILayout.ColorField("Selected Face Color", _faceColor);

		_defaultMaterial = (Material) EditorGUILayout.ObjectField("Default Material", _defaultMaterial, typeof(Material), false);

		defaultOpenInDockableWindow = EditorGUILayout.Toggle("Open in Dockable Window", defaultOpenInDockableWindow);

		GUILayout.BeginHorizontal();
		EditorGUILayout.PrefixLabel("Default Collider");
		defaultColliderType = (int)((ProBuilder.ColliderType)EditorGUILayout.EnumPopup( (ProBuilder.ColliderType)defaultColliderType ));
		GUILayout.EndHorizontal();

		if((ProBuilder.ColliderType)defaultColliderType == ProBuilder.ColliderType.MeshCollider)
			_forceConvex = EditorGUILayout.Toggle("Force Convex Mesh Collider", _forceConvex);

		_showNotifications = EditorGUILayout.Toggle("Show Editor Notifications", _showNotifications);

		pbDragCheckLimit = EditorGUILayout.Toggle(new GUIContent("Limit Drag Check to Selection", "If true, when drag selecting faces, only currently selected pb-Objects will be tested for matching faces.  If false, all pb_Objects in the scene will be checked.  The latter may be slower in large scenes."), pbDragCheckLimit);

		pbForceGridPivot = EditorGUILayout.Toggle(new GUIContent("Force Pivot to Grid", "If true, newly instantiated pb_Objects will have their pivot points set to the first available vertex, ensuring that the object's vertices are placed on-grid."), pbForceGridPivot);

		GUILayout.Space(4);

		GUILayout.Label("Texture Editing Settings", EditorStyles.boldLabel);

		defaultHideFaceMask = EditorGUILayout.Toggle("Hide face mask", defaultHideFaceMask);

		EditorGUILayout.EndScrollView();

		GUILayout.Space(4);

		GUILayout.Label("Shortcut Settings", EditorStyles.boldLabel);

		if(GUI.Button(resetRect, "Use defaults"))
			ResetToDefaults();

		ShortcutSelectPanel();
		ShortcutEditPanel();

		// Save the preferences
		if (GUI.changed)
			SetPrefs();
	}

        public IAsyncResult BeginPoll(int microSeconds,
            SelectMode mode,
            AsyncCallback callback)
        {
            AsyncPollCaller caller = new AsyncPollCaller(Poll);
            //AsyncCallback cb = new AsyncCallback(AsyncPollCallback);

            IAsyncResult result = caller.BeginInvoke(microSeconds, mode, callback, caller);

            return result;
        }

		public PalPanel()
		{
			this.SetStyle(ControlStyles.DoubleBuffer|ControlStyles.UserPaint|ControlStyles.AllPaintingInWmPaint,true);
			myPal = null;
			this.MouseDown+=new MouseEventHandler(mouseDown);
			//Width=(width+2*space)*NumAcross;
			//Height=(height+2*space)*NumAcross;
			clickX=-100;
			clickY=-100;
			selIdx=-1;
			mode = SelectMode.Single;
		}

        public ColorSelectDialog(Control parentCtrl, SelectMode mode)
        {
            InitializeComponent();

            if (mode == SelectMode.Color)
            {
                stampBButton.Visible = false;
                stampSButton.Visible = false;
                this.Width -= 206;
            }

            this.Top = parentCtrl.Top + parentCtrl.Height;
            this.Left = parentCtrl.Left;
        }

        public static void Poll(this Socket socket, SelectMode mode, CancellationToken cancellationToken)
        {
            if (!cancellationToken.CanBeCanceled)
                return;

            if (socket != null)
            {
                do
                {
                    cancellationToken.ThrowIfCancellationRequested();
                } while (!socket.Poll(1000, mode));
            }

            else
                cancellationToken.ThrowIfCancellationRequested();
        }

	static void SetMaterial(SelectMode sm)
	{
		switch(sm)
		{
			case SelectMode.Face:
				selectionMaterial = new Material(Shader.Find("Hidden/ProBuilder/UnlitColor"));
				break;
			case SelectMode.Vertex:
				vertexHandleSize = pb_Preferences_Internal.GetFloat(pb_Constant.pbVertexHandleSize);
				selectionMaterial = new Material(Shader.Find("Hidden/ProBuilder/VertexBillboard"));
				selectionMaterial.SetTexture("_MainTex", (Texture2D)Resources.Load("Textures/VertOff", typeof(Texture2D)));
				break;
		}

		selectionMaterial.SetColor("_Color", faceSelectionColor);	// todo - remove this and use vertex colors
	}

        public SelectCards(Player player, IEnumerable<CardInstance> candidates, SelectMode mode, string message)
            : base(player.Game)
        {
            if (player == null)
            {
                throw new ArgumentNullException("player");
            }
            else if (candidates == null)
            {
                throw new ArgumentNullException("candidates");
            }

            Player = player;
            Candidates = candidates.Where(card => !card.Behaviors.Has<Behaviors.IUnselectable>()).ToList().ToIndexable();
            Message = message ?? String.Empty;
            Mode = mode;
        }

    public static void LoadPrefs()
    {
        _faceColor = pb_Preferences_Internal.GetColor( pb_Constant.pbDefaultFaceColor );

        pbDefaultSelectedVertexColor = pb_Preferences_Internal.GetColor( pb_Constant.pbDefaultSelectedVertexColor );
        pbDefaultVertexColor = pb_Preferences_Internal.GetColor( pb_Constant.pbDefaultVertexColor );

        if(!EditorPrefs.HasKey( pb_Constant.pbDefaultOpenInDockableWindow))
            EditorPrefs.SetBool(pb_Constant.pbDefaultOpenInDockableWindow, true);

        defaultHideFaceMask = (EditorPrefs.HasKey(pb_Constant.pbDefaultHideFaceMask)) ? EditorPrefs.GetBool(pb_Constant.pbDefaultHideFaceMask) : false;

        defaultOpenInDockableWindow = EditorPrefs.GetBool(pb_Constant.pbDefaultOpenInDockableWindow);

        pbDefaultSelectionMode = pb_Preferences_Internal.GetEnum<SelectMode>(pb_Constant.pbDefaultSelectionMode);
        defaultColliderType = (int)pb_Preferences_Internal.GetEnum<ColliderType>(pb_Constant.pbDefaultCollider);

        pbDragCheckLimit 	= pb_Preferences_Internal.GetBool(pb_Constant.pbDragCheckLimit);
        pbForceConvex 		= pb_Preferences_Internal.GetBool(pb_Constant.pbForceConvex);
        pbForceGridPivot 	= pb_Preferences_Internal.GetBool(pb_Constant.pbForceGridPivot);
        pbForceVertexPivot 	= pb_Preferences_Internal.GetBool(pb_Constant.pbForceVertexPivot);

        pbPerimeterEdgeExtrusionOnly = pb_Preferences_Internal.GetBool(pb_Constant.pbPerimeterEdgeExtrusionOnly);
        pbPerimeterEdgeBridgeOnly = pb_Preferences_Internal.GetBool(pb_Constant.pbPerimeterEdgeBridgeOnly);

        pbPBOSelectionOnly = pb_Preferences_Internal.GetBool(pb_Constant.pbPBOSelectionOnly);

        pbVertexHandleSize = pb_Preferences_Internal.GetFloat(pb_Constant.pbVertexHandleSize);

        if(EditorPrefs.HasKey(pb_Constant.pbDefaultMaterial))
        {
            _defaultMaterial = (Material) AssetDatabase.LoadAssetAtPath(pb_Constant.pbDefaultMaterial, typeof(Material));
            if(_defaultMaterial == null)
                _defaultMaterial = pb_Constant.DefaultMaterial;
        }

        defaultShortcuts = EditorPrefs.HasKey(pb_Constant.pbDefaultShortcuts) ?
            pb_Shortcut.ParseShortcuts(EditorPrefs.GetString(pb_Constant.pbDefaultShortcuts)) :
            pb_Shortcut.DefaultShortcuts();

        _showNotifications = EditorPrefs.HasKey(pb_Constant.pbShowEditorNotifications) ?
            EditorPrefs.GetBool(pb_Constant.pbShowEditorNotifications) : true;
    }

 public void RemoveCallback(SelectMode mode, Socket socket)
 {
     lock (_gate)
     {
         switch (mode)
         {
             case SelectMode.SelectRead:
                 _readCallbacks.Remove(socket);
                 break;
             case SelectMode.SelectWrite:
                 var callbackQueue = _writeCallbacks[socket];
                 callbackQueue.Dequeue();
                 if (callbackQueue.Count == 0)
                     _writeCallbacks.Remove(socket);
                 break;
             case SelectMode.SelectError:
                 _errorCallbacks.Remove(socket);
                 break;
             default:
                 throw new ArgumentOutOfRangeException("mode");
         }
     }
 }

        public void AddCallback(SelectMode mode, Socket socket, Action<Socket> callback)
        {
            lock (_gate)
            {
                switch (mode)
                {
                    case SelectMode.SelectRead:
                        _readCallbacks.Add(socket, callback);
                        break;
                    case SelectMode.SelectWrite:
                        Queue<Action<Socket>> callbackQueue;
                        if (!_writeCallbacks.TryGetValue(socket, out callbackQueue))
                            _writeCallbacks.Add(socket, callbackQueue = new Queue<Action<Socket>>());
                        callbackQueue.Enqueue(callback);
                        break;
                    case SelectMode.SelectError:
                        _errorCallbacks.Add(socket, callback);
                        break;
                    default:
                        throw new ArgumentOutOfRangeException("mode");
                }

            }
        }

        public static unsafe SocketError Poll(SafeCloseSocket handle, int microseconds, SelectMode mode, out bool status)
        {
            uint* fdSet = stackalloc uint[Interop.Sys.FD_SETSIZE_UINTS];
            Interop.Sys.FD_ZERO(fdSet);

            Interop.Sys.FD_SET(handle.FileDescriptor, fdSet);

            int fdCount = 0;
            uint* readFds = null;
            uint* writeFds = null;
            uint* errorFds = null;
            switch (mode)
            {
                case SelectMode.SelectRead:
                    readFds = fdSet;
                    fdCount = handle.FileDescriptor + 1;
                    break;

                case SelectMode.SelectWrite:
                    writeFds = fdSet;
                    fdCount = handle.FileDescriptor + 1;
                    break;

                case SelectMode.SelectError:
                    errorFds = fdSet;
                    fdCount = handle.FileDescriptor + 1;
                    break;
            }

            int socketCount = 0;
            Interop.Error err = Interop.Sys.Select(fdCount, readFds, writeFds, errorFds, microseconds, &socketCount);
            if (err != Interop.Error.SUCCESS)
            {
                status = false;
                return GetSocketErrorForErrorCode(err);
            }

            status = Interop.Sys.FD_ISSET(handle.FileDescriptor, fdSet);
            return SocketError.Success;
        }

		/// <summary>
		/// Determines the status of the VirtualSocket.
		/// </summary>
		/// <param name="microSeconds">The time to wait for a response, in microseconds.</param>
		/// <param name="mode">One of the <see cref="SelectMode"/> values.</param>
		/// <returns>See the Socket documentation for the return values.</returns>
		/// <remarks>This property is not supported for SSL/TLS sockets. It can only be used if the SecureProtocol is set to None. Asynchronous behavior in SSL or TLS mode can be achieved by calling the asynchronous methods.</remarks>
		/// <exception cref="NotSupportedException">The mode parameter is not one of the SelectMode values -or- the socket is in SSL or TLS mode.</exception>
		/// <exception cref="SocketException">An operating system error occurs while accessing the VirtualSocket.</exception>
		/// <exception cref="ObjectDisposedException">The VirtualSocket has been closed.</exception>
		/// <remarks>Set microSeconds parameter to a negative integer if you would like to wait indefinitely for a response.</remarks>
		public override bool Poll(int microSeconds, SelectMode mode) {
			if (SecureProtocol != SecureProtocol.None)
				throw new NotSupportedException("The Poll method is not supported in SSL or TLS mode. Use the asynchronous methods and the Available property instead.");
			return base.Poll(microSeconds, mode);
		}

		public abstract bool Poll(int microSeconds, SelectMode mode);

		public bool Poll (int time_us, SelectMode mode)
		{
			if (disposed && closed)
				throw new ObjectDisposedException (GetType ().ToString ());

			if (mode != SelectMode.SelectRead &&
			    mode != SelectMode.SelectWrite &&
			    mode != SelectMode.SelectError)
				throw new NotSupportedException ("'mode' parameter is not valid.");

			int error;
			bool result = Poll_internal (socket, mode, time_us, out error);
			if (error != 0)
				throw new SocketException (error);

			if (mode == SelectMode.SelectWrite && result && !connected) {
				/* Update the connected state; for
				 * non-blocking Connect()s this is
				 * when we can find out that the
				 * connect succeeded.
				 */
				if ((int)GetSocketOption (SocketOptionLevel.Socket, SocketOptionName.Error) == 0) {
					connected = true;
				}
			}
			
			return result;
		}

 public override void SelectObjects(IEnumerable<CamViewState.SelObj> selObjEnum, SelectMode mode = SelectMode.Set)
 {
     base.SelectObjects(selObjEnum, mode);
     DualityEditorApp.Select(this, new ObjectSelection(selObjEnum.Select(s => s.ActualObject)), mode);
 }

        public override void SelectObjects(IEnumerable<CamViewState.SelObj> selObjEnum, SelectMode mode = SelectMode.Set)
        {
            base.SelectObjects(selObjEnum, mode);
            if (!selObjEnum.Any()) return;

            // Change shape selection
            if (selObjEnum.OfType<SelShape>().Any())
            {
                var shapeQuery = selObjEnum.OfType<SelShape>();
                var distinctShapeQuery = shapeQuery.GroupBy(s => s.Body).First(); // Assure there is only one collider active.
                SelShape[] selShapeArray = distinctShapeQuery.ToArray();

                // First, select the associated Collider
                DualityEditorApp.Select(this, new ObjectSelection(selShapeArray[0].Body.GameObj), SelectMode.Set);
                // Then, select actual ShapeInfos
                DualityEditorApp.Select(this, new ObjectSelection(selShapeArray.Select(s => s.ActualObject)), mode);
            }

            // Change collider selection
            else if (selObjEnum.OfType<SelBody>().Any())
            {
                // Deselect ShapeInfos
                DualityEditorApp.Deselect(this, ObjectSelection.Category.Other);
                // Select Collider
                DualityEditorApp.Select(this, new ObjectSelection(selObjEnum.OfType<SelBody>().Select(s => s.ActualObject)), mode);
            }
        }

 /// <summary>
 /// 学籍异动类型
 /// </summary>
 /// <returns></returns>
 public static SelectList StudentEnrolmentChangeTypeList(SelectMode mode = SelectMode.Default)
 {
     return SelectListFactory.ToSelectList(mode, _studentEnrolmentChangeTypes);
 }