曲线逻辑

MonitorModule/ViewModels/MonitorChannel.cs

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+using OxyPlot.Series;
+using OxyPlot;
+using System.Collections.Concurrent;
+using Prism.Mvvm;
+using NCalc;
+
+namespace MonitorModule.ViewModels
+{
+    /// <summary>
+    /// 监测通道：一个设备方法对应一个通道。
+    /// 数据记录（DataPoints）与图表显示（Series）完全分离：
+    ///   - IsMonitored=true 时始终记录 DataPoints
+    ///   - IsDisplayed=true 时才创建 LineSeries 并绘制
+    /// </summary>
+    public class MonitorChannel : BindableBase
+    {
+        // ===== 标识 =====
+        public string DeviceName { get; init; } = string.Empty;
+        public string MethodName { get; init; } = string.Empty;
+        public string DisplayName { get; init; } = string.Empty;
+
+        // ===== 状态 =====
+        private bool _isMonitored = true;
+        /// <summary>是否在记录数据点（添加后始终为 true）</summary>
+        public bool IsMonitored
+        {
+            get => _isMonitored;
+            set => SetProperty(ref _isMonitored, value);
+        }
+
+        private bool _isDisplayed = true;
+        /// <summary>是否在 OxyPlot 上显示</summary>
+        public bool IsDisplayed
+        {
+            get => _isDisplayed;
+            set => SetProperty(ref _isDisplayed, value);
+        }
+
+        // ===== 数学变换 =====
+        private string? _mathExpression;
+        /// <summary>可选数学变换表达式，如 "x*0.001"。为空则 DisplayValue=RawValue</summary>
+        public string? MathExpression
+        {
+            get => _mathExpression;
+            set => SetProperty(ref _mathExpression, value);
+        }
+
+        // ===== 颜色 =====
+        public OxyColor Color { get; set; } = OxyColors.SteelBlue;
+
+        // ===== 数据存储 =====
+        /// <summary>所有采样数据点（线程安全），与 OxyPlot 无关</summary>
+        public ConcurrentQueue<(double Time, double RawValue, double DisplayValue)> DataPoints { get; } = new();
+
+        /// <summary>最大缓冲数据点数，超出则丢弃最旧的</summary>
+        public int MaxBuffer { get; set; } = 5000;
+
+        // ===== OxyPlot Series（仅 IsDisplayed=true 时存在）=====
+        private LineSeries? _series;
+        public LineSeries? Series
+        {
+            get => _series;
+            set => SetProperty(ref _series, value);
+        }
+
+        // ===== 辅助方法 =====
+        /// <summary>记录一个数据点：RawValue 经数学变换后得到 DisplayValue，一并入队</summary>
+        public void Record(double time, double rawValue)
+        {
+            double displayValue = rawValue;
+            if (!string.IsNullOrWhiteSpace(MathExpression))
+            {
+                try
+                {
+                    var expr = new NCalc.Expression(MathExpression);
+                    expr.Parameters["x"] = rawValue;
+                    var result = expr.Evaluate();
+                    displayValue = Convert.ToDouble(result);
+                }
+                catch
+                {
+                    displayValue = rawValue;
+                }
+            }
+
+            DataPoints.Enqueue((time, rawValue, displayValue));
+
+            // 超出缓冲上限时批量丢弃旧数据
+            while (DataPoints.Count > MaxBuffer)
+            {
+                DataPoints.TryDequeue(out _);
+            }
+
+            // 如果正在显示，同步到 Series
+            if (_series != null)
+            {
+                _series.Points.Add(new DataPoint(time, displayValue));
+                while (_series.Points.Count > 200)
+                {
+                    _series.Points.RemoveAt(0);
+                }
+            }
+        }
+    }
+}