解决stepsmanager bug

TestingModule/ViewModels/StepsManagerViewModel.cs

@@ -4,6 +4,8 @@ using System;
 using System.Collections;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
+using System.Collections.Specialized;
+using System.ComponentModel;
 using System.Linq;
 using System.Reflection;
 using System.Text;
@@ -79,6 +81,10 @@ namespace TestingModule.ViewModels
         private readonly GlobalInfo _globalInfo;
         private List<StepVM> tmpCopyList = new List<StepVM>();
 
+        // 追踪当前订阅的集合实例，用于在集合被整体替换时重新订阅
+        private ObservableCollection<StepVM> _trackedStepCollection;
+        private ObservableCollection<StepVM> _trackedErrorStepCollection;
+
 
         #endregion
         #region 命令
@@ -101,8 +107,8 @@ namespace TestingModule.ViewModels
             DeleteStepCommand = new DelegateCommand(DeleteStep);
             TabSelectionChangedCommand = new DelegateCommand<string>(TabSelectionChanged);
             SelectionChangedCommand = new DelegateCommand<object>(SelectionChanged);
-            Program.StepCollection.CollectionChanged += StepCollection_CollectionChanged;
-            Program.ErrorStepCollection.CollectionChanged += StepCollection_CollectionChanged;
+            SubscribeStepCollections();
+            Program.PropertyChanged += Program_PropertyChanged;
             Admin = _globalInfo.IsAdmin;
             _eventAggregator.GetEvent<AlarmEvent>().Subscribe(() =>
             {
@@ -206,13 +212,67 @@ namespace TestingModule.ViewModels
         #endregion
 
         #region 辅助方法
-        private void StepCollection_CollectionChanged(object? sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
+
+        /// <summary>
+        /// 订阅当前 Program 的 StepCollection 和 ErrorStepCollection 的 CollectionChanged 事件。
+        /// </summary>
+        private void SubscribeStepCollections()
+        {
+            _trackedStepCollection = Program.StepCollection;
+            _trackedErrorStepCollection = Program.ErrorStepCollection;
+
+            if (_trackedStepCollection != null)
+                _trackedStepCollection.CollectionChanged += StepCollection_CollectionChanged;
+            if (_trackedErrorStepCollection != null)
+                _trackedErrorStepCollection.CollectionChanged += StepCollection_CollectionChanged;
+        }
+
+        /// <summary>
+        /// 取消订阅当前追踪的集合事件。
+        /// </summary>
+        private void UnsubscribeStepCollections()
+        {
+            if (_trackedStepCollection != null)
+            {
+                _trackedStepCollection.CollectionChanged -= StepCollection_CollectionChanged;
+                _trackedStepCollection = null;
+            }
+            if (_trackedErrorStepCollection != null)
+            {
+                _trackedErrorStepCollection.CollectionChanged -= StepCollection_CollectionChanged;
+                _trackedErrorStepCollection = null;
+            }
+        }
+
+        /// <summary>
+        /// 当 Program 的 StepCollection / ErrorStepCollection 被整体替换时，自动重新订阅并刷新序号。
+        /// </summary>
+        private void Program_PropertyChanged(object? sender, PropertyChangedEventArgs e)
+        {
+            if (e.PropertyName == nameof(ProgramVM.StepCollection) ||
+                e.PropertyName == nameof(ProgramVM.ErrorStepCollection))
+            {
+                UnsubscribeStepCollections();
+                SubscribeStepCollections();
+
+                // 集合被整体替换后，对新集合重新编号
+                Application.Current?.Dispatcher.BeginInvoke(new Action(() =>
+                {
+                    for (int i = 0; i < Program.StepCollection.Count; i++)
+                        Program.StepCollection[i].Index = i + 1;
+                    for (int i = 0; i < Program.ErrorStepCollection.Count; i++)
+                        Program.ErrorStepCollection[i].Index = i + 1;
+                }), System.Windows.Threading.DispatcherPriority.Background);
+            }
+        }
+
+        private void StepCollection_CollectionChanged(object? sender, NotifyCollectionChangedEventArgs e)
         {
             var collection = sender as ObservableCollection<StepVM>;
             // Add/Move/Remove 都会触发，这里判断具体情形
-            if (e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Add ||
-                e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Move||
-                 e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Remove)
+            if (e.Action == NotifyCollectionChangedAction.Add ||
+                e.Action == NotifyCollectionChangedAction.Move||
+                 e.Action == NotifyCollectionChangedAction.Remove)
             {
                 // 如果需要等 UI 更新完再处理，可也用 Dispatcher 延迟一小段时间
                 Application.Current?.Dispatcher.BeginInvoke(new Action(() =>
@@ -238,31 +298,27 @@ namespace TestingModule.ViewModels
         {
             try
             {
-                // 1. 【核心修复】必须取消订阅 CollectionChanged 事件，否则 VM 永远无法被释放
+                // 1. 取消订阅 CollectionChanged 事件（从追踪的实例上取消，而非可能已被替换的当前实例）
+                UnsubscribeStepCollections();
+
+                // 2. 取消订阅 Program.PropertyChanged
                 if (Program != null)
                 {
-                    if (Program.StepCollection != null)
-                    {
-                        Program.StepCollection.CollectionChanged -= StepCollection_CollectionChanged;
-                    }
-                    if (Program.ErrorStepCollection != null)
-                    {
-                        Program.ErrorStepCollection.CollectionChanged -= StepCollection_CollectionChanged;
-                    }
+                    Program.PropertyChanged -= Program_PropertyChanged;
                 }
 
-                // 2. 【核心修复】必须显式退订 Prism 全局事件（AlarmEvent）
+                // 3. 【核心修复】必须显式退订 Prism 全局事件（AlarmEvent）
                 // 注意：因为订阅时使用的是匿名 Lambda，最安全稳妥的退订方式是把整个事件上的当前 VM 订阅者全部注销
                 _eventAggregator?.GetEvent<AlarmEvent>()?.Unsubscribe(null);
 
-                // 3. 清空临时缓存集合与 UI 绑定列表，避免悬挂指针
+                // 4. 清空临时缓存集合与 UI 绑定列表，避免悬挂指针
                 tmpCopyList?.Clear();
                 tmpCopyList = null!;
 
                 SelectedItems?.Clear();
                 SelectedItems = null!;
 
-                // 4. 清除选中项状态引用
+                // 5. 清除选中项状态引用
                 SelectedStep = null;
                 if (_ScopedContext != null)
                 {