使用新框架与技术代替旧框架与技术，实现涂装车间后道标签扫码程序

RIZO_Application.Modules.LogModule/ViewModels/SystemLogViewModel.cs

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+using System;
+using System.Diagnostics;
+using System.Text;
+using NLog;
+using Prism.Events;
+using Prism.Regions;
+using RIZO_Application.Core;
+using RIZO_Application.Core.Mvvm;
+
+namespace RIZO_Application.Modules.LogModule.ViewModels
+{
+    public class SystemLogViewModel : RegionViewModelBase
+    {
+        private readonly IEventAggregator _eventAggregator;
+        private SubscriptionToken _token;
+        private readonly StringBuilder _logMessageBuilder = new StringBuilder();
+        private Logger _logger = LogManager.GetCurrentClassLogger();
+        private const int MaxLogLength = 1000; // 假设最大长度为1000，可以根据实际情况调整
+        private const string LogFormat = "\n{0}: {1}";
+
+        // 定义一个日志更新事件
+        public event EventHandler LogUpdated;
+
+        public string LogMessage
+        {
+            get { return _logMessageBuilder.ToString(); }
+            set
+            {
+                _logMessageBuilder.Clear();
+                _logMessageBuilder.Append(value);
+                RaisePropertyChanged(nameof(LogMessage));
+            }
+        }
+
+        public SystemLogViewModel(
+            IRegionManager regionManager,
+            IEventAggregator eventAggregator)
+            : base(regionManager)
+        {
+            OnLogReceived("初始化日志系统");
+            _eventAggregator = eventAggregator;
+            // 订阅事件，使用UI线程处理，保持强引用
+            _token = _eventAggregator.GetEvent<SystemLogEvent>().Subscribe(OnLogReceived, ThreadOption.UIThread, true);
+        }
+
+        private void OnLogReceived(string message)
+        {
+            string newLog = string.Format(LogFormat, DateTime.Now, message);
+            _logMessageBuilder.Append(newLog);
+
+            if (_logMessageBuilder.Length > MaxLogLength)
+            {
+                // 计算需要截取的位置，保留最新的日志
+                int startIndex = Math.Max(0, _logMessageBuilder.Length - MaxLogLength);
+                _logMessageBuilder.Remove(0, startIndex);
+            }
+
+            RaisePropertyChanged(nameof(LogMessage));
+            _logger.Info(newLog);
+
+            // 触发日志更新事件
+            OnLogUpdated();
+        }
+
+        protected virtual void OnLogUpdated()
+        {
+            LogUpdated?.Invoke(this, EventArgs.Empty);
+        }
+
+        public void Destroy()
+        {
+            _token?.Dispose();
+        }
+
+        public void AddTestLogMessage()
+        {
+            // 示例实现，可根据需求修改
+            OnLogReceived("测试日志消息");
+        }
+
+        public override void OnNavigatedTo(NavigationContext navigationContext)
+        {
+            //do something
+        }
+    }
+}