清理引用，将NavigatorServices更改为使用Message来实现导航的切换

Services/DemoBackgroundService.cs

@@ -1,37 +1,21 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-using CommunityToolkit.Mvvm.ComponentModel;
-using CommunityToolkit.Mvvm.Messaging;
-using Microsoft.Extensions.Hosting;
-using PMSWPF.Message;
+using Microsoft.Extensions.Hosting;
 
-namespace PMSWPF.Services
+namespace PMSWPF.Services;
+
+internal class DemoBackgroundService : BackgroundService
 {
-    internal class DemoBackgroundService : BackgroundService
+    private int count = 0;
+
+
+    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
     {
-        int count = 0;
-
-        public DemoBackgroundService()
-        {
-
-        }
-
-
-
-        protected override async Task ExecuteAsync(CancellationToken stoppingToken)
-        {
-
-            while (!stoppingToken.IsCancellationRequested)
-            {
-                await Task.Delay(1000);
-                count += 1;
-                var msg = new MyMessage(35) { Count = count };
-                WeakReferenceMessenger.Default.Send<MyMessage>(msg);
-                Console.WriteLine("Hello");
-            }
-        }
+        // while (!stoppingToken.IsCancellationRequested)
+        // {
+        //     await Task.Delay(1000);
+        //     count += 1;
+        //     var msg = new MyMessage(35) { Count = count };
+        //     WeakReferenceMessenger.Default.Send<MyMessage>(msg);
+        //     Console.WriteLine("Hello");
+        // }
     }
-}
+}