实现VariableHistoryView中图表的动态更新

DMS.WPF/ViewModels/VariableHistoryViewModel.cs

@@ -108,21 +108,28 @@ partial class VariableHistoryViewModel : ViewModelBase, INavigatable
 
     private void OnVariableValueChanged(object? sender, VariableValueChangedEventArgs e)
     {
-        // if (e.Variable.Id != CurrentVariable.Id)
+        if (e.Variable.Id != CurrentVariable.Id)
-        // {
+        {
-        //     return;
+            return;
-        // }
+        }
-        //
+
-        // var variableHistory = new VariableHistoryDto()
+        var variableHistory = new VariableHistoryDto()
-        //                       {
+                              {
-        //                           VariableId = CurrentVariable.Id,
+                                  VariableId = CurrentVariable.Id,
-        //                           Timestamp = DateTime.Now,
+                                  Timestamp = DateTime.Now,
-        //                           Value = e.Variable.DataValue
+                                  Value = e.Variable.DisplayValue
-        //                       };
+                              };
-        // _variableHistoryList.Add(variableHistory);
+        _variableHistoryList.Add(variableHistory);
-        //
+
-        // // 更新图表数据
+        // 限制历史记录数量以防止内存溢出
-        // UpdateChartData();
+        if (HistoryLimit.HasValue && _variableHistoryList.Count > HistoryLimit.Value)
+        {
+            // 移除最旧的记录
+            _variableHistoryList.RemoveAt(0);
+        }
+
+        // 更新图表数据
+        UpdateChartData();
     }
 
     /// <summary>
@@ -241,6 +248,9 @@ partial class VariableHistoryViewModel : ViewModelBase, INavigatable
             return;
         }
 
+        // 如果系列集合为空或没有有效的系列，则重新创建
+        if (LineSeriesCollection == null || LineSeriesCollection.Length == 0)
+        {
             // 创建数值点集合
             var values = new List<DateTimePoint>();
             
@@ -266,6 +276,27 @@ partial class VariableHistoryViewModel : ViewModelBase, INavigatable
 
             // 更新序列集合
             LineSeriesCollection = new ISeries[] { series };
+        }
+        else
+        {
+            // 对于实时更新，保持原有完整的更新逻辑以确保数据一致性
+            // 创建数值点集合
+            var values = new List<DateTimePoint>();
+            
+            foreach (var history in _variableHistoryList)
+            {
+                // 尝试将值转换为double
+                if (double.TryParse(history.Value, out double value))
+                {
+                    values.Add(new DateTimePoint(history.Timestamp, value));
+                }
+            }
+
+            // 更新当前系列
+            var currentSeries = (LineSeries<DateTimePoint>)LineSeriesCollection[0];
+            currentSeries.Values = values;
+            currentSeries.Name = CurrentVariable?.Name ?? "变量值";
+        }
 
         // 更新坐标轴
         LineAxisX = new Axis[]