refactor: 重构翻页屏逻辑，解决信息更新不及时问题

CRSim.ScreenSimulator/ViewModels/BaseScreenViewModel.cs

@@ -4,59 +4,29 @@ using CRSim.Core.Models;
 using CRSim.ScreenSimulator.Abstractions;
 using CRSim.ScreenSimulator.Models;
 using System.Collections.ObjectModel;
-using System.Linq;
-using System.Windows;
 
 namespace CRSim.ScreenSimulator.ViewModels
 {
-    public partial class BaseScreenViewModel : ObservableObject,IScreenViewModel
+    public partial class BaseScreenViewModel : ObservableObject, IScreenViewModel
     {
         public ITimeService TimeService { get; set; }
         public readonly Settings _settings;
         public readonly TaskCompletionSource<bool> DataLoaded = new();
-        [ObservableProperty]
-        private DateTime _currentTime = new();
-        [ObservableProperty]
-        private string _text = "";
-        [ObservableProperty]
-        public int _location;
-        [ObservableProperty]
-        private Station _thisStation;
-        [ObservableProperty]
-        private string _thisPlatform;
-        [ObservableProperty]
-        private string _thisTicketCheck;
-        [ObservableProperty]
-        private Uri _video;
+
+        [ObservableProperty] private DateTime _currentTime = new();
+        [ObservableProperty] private string _text = "";
+        [ObservableProperty] public int _location;
+        [ObservableProperty] private Station _thisStation;
+        [ObservableProperty] private string _thisPlatform;
+        [ObservableProperty] private string _thisTicketCheck;
+        [ObservableProperty] private Uri _video;
+        [ObservableProperty] private int _currentPageIndex = 0;
+
         public ObservableCollection<TrainInfo> ScreenA { get; private set; } = [];
-        public ObservableCollection<TrainInfo> ScreenB { get; private set; } = []; 
+        public ObservableCollection<TrainInfo> ScreenB { get; private set; } = [];
         public System.Windows.Threading.Dispatcher UIDispatcher { get; set; }
-
         public List<TrainInfo> TrainInfo { get; set; } = [];
-
         public StationType StationType = StationType.Both;
-
-        protected BaseScreenViewModel(ITimeService timeService, ISettingsService settingsService)
-        {
-
-            TimeService = timeService;
-            _settings = settingsService.GetSettings();
-
-            TimeService.OneSecondElapsed += OnTimeElapsed;
-
-            TimeService.RefreshSecondsElapsed += RefreshData;
-            TimeService.RefreshSecondsElapsed += RefreshDisplay;
-            Initialize();
-        }
-        [ObservableProperty]
-        private int _currentPageIndex = 0;
-        public int PageCount
-        {
-            get
-            {
-                return Math.Min((int)Math.Ceiling((double)TrainInfo.Count / ItemsPerPage * ScreenCount.Value),_settings.MaxPages);
-            }
-        }
         public int ItemsPerPage = 1;
 
         //<summary>
@@ -64,67 +34,170 @@ namespace CRSim.ScreenSimulator.ViewModels
         //</summary>
         public int? ScreenCount = null;
 
-        private async void Initialize()
+        private TrainInfo nullTrainInfo = new();
+
+        public int PageCount
         {
-            await DataLoaded.Task;
-            RefreshDisplay(null, null);
-        }
-        public void RefreshData(object? sender, EventArgs e)
-        {
-            if (CurrentPageIndex == 0)
+            get
             {
-                List<TrainInfo> itemsToRemove = [];
-                foreach(TrainInfo trainInfo in TrainInfo)
-                {
-                    if (trainInfo.DepartureTime == null)
-                    {
-                        if (trainInfo.ArrivalTime.Value.Add(_settings.StopDisplayFromArrivalDuration) < TimeService.GetDateTimeNow())
-                        {
-                            itemsToRemove.Add(trainInfo);
-                        }
-                    }
-                    else
-                    {
-                        if ((StationType == StationType.Arrival || StationType == StationType.Both ? trainInfo.DepartureTime.Value : trainInfo.DepartureTime.Value.Subtract(_settings.StopDisplayUntilDepartureDuration)) < TimeService.GetDateTimeNow())
-                        {
-                            itemsToRemove.Add(trainInfo);
-                        }
-                    }
-                }
-                foreach (var item in itemsToRemove)
-                {
-                    TrainInfo.Remove(item);
-                }
+                if (ScreenCount == null || ScreenCount == 0) return 1;
+                return Math.Min((int)Math.Ceiling((double)TrainInfo.Count / (ItemsPerPage * ScreenCount.Value)), _settings.MaxPages);
             }
         }
 
+        protected BaseScreenViewModel(ITimeService timeService, ISettingsService settingsService)
+        {
+            TimeService = timeService;
+            _settings = settingsService.GetSettings();
+
+            // 每秒执行一次：包含数据清理和 UI 重建
+            TimeService.OneSecondElapsed += OnTimeElapsed;
+
+            // 仅执行翻页逻辑（例如每 10 秒切换一次页码）
+            TimeService.RefreshSecondsElapsed += RefreshDisplay;
+
+            Initialize();
+        }
+
+        private async void Initialize()
+        {
+            await DataLoaded.Task;
+            UpdateVisuals(); // 初始渲染
+        }
+
+        /// <summary>
+        /// 每秒触发的核心逻辑
+        /// </summary>
         private void OnTimeElapsed(object? sender, EventArgs e)
         {
             CurrentTime = TimeService.GetDateTimeNow();
-            OnPropertyChanged(nameof(ScreenA));
-            OnPropertyChanged(nameof(ScreenB));
+
+            // 1. 检查并删除过期车次
+            CleanExpiredData();
+
+            // 2. 重新构建显示内容（清空并重新添加）
+            UpdateVisuals();
         }
 
+        /// <summary>
+        /// 仅负责翻页更改索引
+        /// </summary>
+        public virtual void RefreshDisplay(object? sender, EventArgs e)
+        {
+            int totalPages = PageCount;
+            if (totalPages <= 1)
+            {
+                CurrentPageIndex = 0;
+                return;
+            }
+
+            // 循环翻页逻辑
+            CurrentPageIndex = (CurrentPageIndex + 1 >= totalPages) ? 0 : CurrentPageIndex + 1;
+        }
+
+        /// <summary>
+        /// 核心渲染方法：删除所有元素并根据当前 PageIndex 重新填充
+        /// </summary>
+        private void UpdateVisuals()
+        {
+            UIDispatcher.Invoke(() =>
+            {
+                // 清空当前显示的所有元素
+                ScreenA.Clear();
+                ScreenB.Clear();
+
+                if (ScreenCount == null)
+                {
+                    // 非翻页模式：始终显示前 N 条
+                    for (int i = 0; i < ItemsPerPage; i++)
+                    {
+                        ScreenA.Add(TrainInfo.Count > i ? TrainInfo[i] : nullTrainInfo);
+                    }
+                    return;
+                }
+
+                // 翻页模式：根据 CurrentPageIndex 计算起始点
+                int startIndex = CurrentPageIndex * ItemsPerPage * ScreenCount.Value;
+
+                // 填充 ScreenA
+                var leftItems = TrainInfo.Skip(startIndex).Take(ItemsPerPage).ToList();
+                while (leftItems.Count < ItemsPerPage) leftItems.Add(nullTrainInfo);
+                foreach (var item in leftItems) ScreenA.Add(item);
+
+                // 如果是双屏模式，填充 ScreenB
+                if (ScreenCount >= 2)
+                {
+                    var rightItems = TrainInfo.Skip(startIndex + ItemsPerPage).Take(ItemsPerPage).ToList();
+                    while (rightItems.Count < ItemsPerPage) rightItems.Add(nullTrainInfo);
+                    foreach (var item in rightItems) ScreenB.Add(item);
+                }
+            });
+        }
+
+        /// <summary>
+        /// 数据清理逻辑：检查并移除不再需要显示的车次
+        /// </summary>
+        private void CleanExpiredData()
+        {
+            var now = TimeService.GetDateTimeNow();
+            bool changed = false;
+
+            // 使用倒序或创建临时列表移除，防止遍历冲突
+            for (int i = TrainInfo.Count - 1; i >= 0; i--)
+            {
+                var train = TrainInfo[i];
+                bool shouldRemove = false;
+
+                if (train.DepartureTime == null) // 终到车
+                {
+                    if (train.ArrivalTime.Value.Add(_settings.StopDisplayFromArrivalDuration) < now)
+                        shouldRemove = true;
+                }
+                else // 始发或过路车
+                {
+                    var referenceTime = (StationType == StationType.Arrival || StationType == StationType.Both)
+                                        ? train.DepartureTime.Value
+                                        : train.DepartureTime.Value.Subtract(_settings.StopDisplayUntilDepartureDuration);
+
+                    if (referenceTime < now)
+                        shouldRemove = true;
+                }
+
+                if (shouldRemove)
+                {
+                    TrainInfo.RemoveAt(i);
+                    changed = true;
+                }
+            }
+
+            // 如果删除了数据导致总页数变少，重置索引防止越界
+            if (changed && CurrentPageIndex >= PageCount)
+            {
+                CurrentPageIndex = 0;
+            }
+        }
+
+        /// <summary>
+        /// 原始数据加载（保持不变）
+        /// </summary>
         public void LoadData(Station station, TicketCheck? ticketCheck, string platform)
         {
             ThisStation = station;
             ThisPlatform = platform;
             ThisTicketCheck = ticketCheck?.Name;
+
             var trains = station.TrainStops;
             foreach (var trainNumber in trains)
             {
-
                 if (trainNumber != null &&
-                    (StationType == StationType.Both ||
-                    trainNumber.StationType == StationType.Both ||
-                    StationType == trainNumber.StationType) &&
+                    (StationType == StationType.Both || trainNumber.StationType == StationType.Both || StationType == trainNumber.StationType) &&
                     (ticketCheck == null || trainNumber.TicketCheckIds.Contains(ticketCheck.Id)) &&
                     (platform == string.Empty || trainNumber.Platform == platform))
                 {
                     var now = TimeService.GetDateTimeNow();
                     var today = now.Date;
 
-                    if (_settings.LoadTodayOnly && today.Add((trainNumber.DepartureTime??trainNumber.ArrivalTime)!.Value).Add(trainNumber.Status.Value) < now)
+                    if (_settings.LoadTodayOnly && today.Add((trainNumber.DepartureTime ?? trainNumber.ArrivalTime)!.Value).Add(trainNumber.Status.Value) < now)
                     {
                         continue;
                     }
@@ -137,101 +210,26 @@ namespace CRSim.ScreenSimulator.ViewModels
                         TrainNumber = trainNumber.Number,
                         Terminal = trainNumber.Terminal,
                         Origin = trainNumber.Origin,
-                        ArrivalTime = AdjustTime(trainNumber.ArrivalTime,trainNumber.Status),
+                        ArrivalTime = AdjustTime(trainNumber.ArrivalTime, trainNumber.Status),
                         DepartureTime = trainNumber.Status > TimeSpan.Zero ? AdjustTime(trainNumber.DepartureTime, trainNumber.Status) : AdjustTime(trainNumber.DepartureTime, TimeSpan.Zero),
                         TicketChecks = trainNumber.TicketCheckIds is null ? [] : [.. station.WaitingAreas
                             .SelectMany(w => w.TicketChecks)
                             .Where(tc => trainNumber.TicketCheckIds.Contains(tc.Id))
                             .Select(tc => tc.Name)],
-                        WaitingArea = trainNumber.StationType == StationType.Arrival ? string.Empty : string.Join(" ", station.WaitingAreas.Where(x => x.TicketChecks.Any(y => trainNumber.TicketCheckIds.Contains(y.Id))).Select(x=>x.Name)),
+                        WaitingArea = trainNumber.StationType == StationType.Arrival ? string.Empty : string.Join(" ", station.WaitingAreas.Where(x => x.TicketChecks.Any(y => trainNumber.TicketCheckIds.Contains(y.Id))).Select(x => x.Name)),
                         Platform = trainNumber.Platform,
                         Length = trainNumber.Length,
                         Landmark = trainNumber.Landmark,
                         State = trainNumber.Status
                     });
-
                 }
             }
-            if(StationType == StationType.Arrival)
-            {
-                TrainInfo = [.. TrainInfo.OrderBy(x => x.ArrivalTime??x.DepartureTime)];
-            }
-            else
-            {
-                TrainInfo = [.. TrainInfo.OrderBy(x => x.DepartureTime??x.ArrivalTime)];
-            }
-            RefreshData(null, null);
+
+            TrainInfo = StationType == StationType.Arrival
+                ? [.. TrainInfo.OrderBy(x => x.ArrivalTime ?? x.DepartureTime)]
+                : [.. TrainInfo.OrderBy(x => x.DepartureTime ?? x.ArrivalTime)];
+
             DataLoaded.SetResult(true);
         }
-        public virtual void RefreshDisplay(object? sender, EventArgs e)
-        {
-            UIDispatcher.Invoke(() =>
-            {
-                if (ScreenCount == null)
-                {
-                    for (int i = 0; i < ItemsPerPage; i++)
-                    {
-                        ScreenA.Add(TrainInfo.Count > i ? TrainInfo[i] : new());
-                    }
-                    if (ScreenA.Count > ItemsPerPage)
-                    {
-                        for (int i = 0; i < ItemsPerPage; i++)
-                        {
-                            ScreenA.RemoveAt(0);
-                        }
-                    }
-                    return;
-                }
-                int pageCount = (int)Math.Ceiling((double)TrainInfo.Count / (ItemsPerPage * ScreenCount.Value));
-                int startIndex = CurrentPageIndex * ItemsPerPage * ScreenCount.Value;
-
-                switch (ScreenCount)
-                {
-                    case 1:
-                        {
-                            ScreenA.Clear();
-                            var items = TrainInfo.Skip(startIndex).Take(ItemsPerPage).ToList();
-                            while (items.Count < ItemsPerPage)
-                            {
-                                items.Add(new TrainInfo());
-                            }
-                            foreach (var item in items)
-                            {
-                                ScreenA.Add(item);
-                            }
-                            break;
-                        }
-                    case 2:
-                        {
-                            ScreenA.Clear();
-                            ScreenB.Clear();
-
-                            var leftItems = TrainInfo.Skip(startIndex).Take(ItemsPerPage).ToList();
-                            while (leftItems.Count < ItemsPerPage)
-                            {
-                                leftItems.Add(new TrainInfo());
-                            }
-                            foreach (var item in leftItems)
-                            {
-                                ScreenA.Add(item);
-                            }
-
-                            var rightItems = TrainInfo.Skip(startIndex + ItemsPerPage).Take(ItemsPerPage).ToList();
-                            while (rightItems.Count < ItemsPerPage)
-                            {
-                                rightItems.Add(new TrainInfo());
-                            }
-                            foreach (var item in rightItems)
-                            {
-                                ScreenB.Add(item);
-                            }
-                            break;
-                        }
-                }
-
-                CurrentPageIndex = CurrentPageIndex + 1 >= Math.Min(_settings.MaxPages, pageCount) ? 0 : CurrentPageIndex + 1;
-            });
-        }
-
     }
-}
+}