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

Data/DbContext.cs

@@ -1,25 +1,25 @@
 using SqlSugar;
 
-namespace PMSWPF.Data
-{
-    public class DbContext
-    {
-        private static SqlSugarClient _db;
+namespace PMSWPF.Data;
 
-        public static SqlSugarClient GetInstance()
+public class DbContext
+{
+    private static SqlSugarClient _db;
+
+    public static SqlSugarClient GetInstance()
+    {
+        if (_db == null)
         {
-            if (_db == null)
+            var connectionString = "server=127.0.0.1;port=3306;user=root;password=Pgw15221236646; database=pmswpf;";
+            _db = new SqlSugarClient(new ConnectionConfig
             {
-                string connectionString = "server=127.0.0.1;port=3306;user=root;password=Pgw15221236646; database=pmswpf;";
-                _db = new SqlSugarClient(new ConnectionConfig()
-                {
-                    ConnectionString = connectionString,
-                    DbType = DbType.MySql, // 根据实际数据库类型修改，如DbType.MySql等
-                    IsAutoCloseConnection = true,
-                    InitKeyType = InitKeyType.Attribute
-                });
-            }
-            return _db;
+                ConnectionString = connectionString,
+                DbType = DbType.MySql, // 根据实际数据库类型修改，如DbType.MySql等
+                IsAutoCloseConnection = true,
+                InitKeyType = InitKeyType.Attribute
+            });
         }
+
+        return _db;
     }
-}
+}