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

Message/MyMessage.cs

@@ -1,20 +1,12 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-using CommunityToolkit.Mvvm.Messaging.Messages;
+using CommunityToolkit.Mvvm.Messaging.Messages;
 
-namespace PMSWPF.Message
+namespace PMSWPF.Message;
+
+public class MyMessage : ValueChangedMessage<int>
 {
-    public class MyMessage : ValueChangedMessage<int>
+    public MyMessage(int value) : base(value)
     {
-        private int count;
-
-        public MyMessage(int value) : base(value)
-        {
-        }
-
-        public int Count { get => count; set => count = value; }
     }
-}
+
+    public int Count { get; set; }
+}

Message/NavgatorMessage.cs

@@ -0,0 +1,11 @@
+using CommunityToolkit.Mvvm.Messaging.Messages;
+using PMSWPF.ViewModels;
+
+namespace PMSWPF.Message;
+
+public class NavgatorMessage : ValueChangedMessage<ViewModelBase>
+{
+    public NavgatorMessage(ViewModelBase value) : base(value)
+    {
+    }
+}

Message/NotificationMessage.cs

@@ -3,13 +3,15 @@ using PMSWPF.Enums;
 
 namespace PMSWPF.Message;
 
-public class NotificationMessage:ValueChangedMessage<string>
+public class NotificationMessage : ValueChangedMessage<string>
 {
+    public NotificationMessage(string msg, NotificationType type = NotificationType.Info, bool isGlobal = false) :
+        base(msg)
+    {
+        Type = type;
+        IsGlobal = isGlobal;
+    }
+
     public NotificationType Type { get; set; }
     public bool IsGlobal { get; set; }
-    public NotificationMessage(string msg,NotificationType type=NotificationType.Info,bool isGlobal=false) : base(msg)
-    {
-        this.Type = type;
-        this.IsGlobal = isGlobal;
-    }
 }

Message/ReqMessage.cs

@@ -1,13 +1,13 @@
 using CommunityToolkit.Mvvm.Messaging.Messages;
 
-namespace PMSWPF.Message
+namespace PMSWPF.Message;
+
+public class ReqMessage : RequestMessage<int>
 {
-    public class ReqMessage : RequestMessage<int>
+    public ReqMessage(int count)
     {
-        public int Count { get; set; }
-        public ReqMessage(int count)
-        {
-            Count = count;
-        }
+        Count = count;
     }
-}
+
+    public int Count { get; set; }
+}