Merge pull request PCL-Community#114 from LaoSparrow/feat-navigation

重构 NavigationService && 修复页面切换动画

Author: LaoSparrow

PCL.Neo/App.axaml.cs

@@ -72,7 +72,7 @@ public override void OnFrameworkInitializationCompleted()
                 DisableAvaloniaDataAnnotationValidation();
                 desktop.MainWindow = new MainWindow { DataContext = vm };
                 // 由于导航改成了异步方法，在构造函数中无法正常导向首页，需要在此处导向
-                Ioc.Default.GetRequiredService<INavigationService>().GotoAsync<HomeViewModel>();
+                Ioc.Default.GetRequiredService<INavigationService>().GoToAsync<HomeViewModel>().Wait(); // TODO: idk if this is appropriate
             }
 
             base.OnFrameworkInitializationCompleted();

PCL.Neo/Messages/NavigationMessage.cs

@@ -0,0 +1,27 @@
+using PCL.Neo.Services;
+using PCL.Neo.ViewModels;
+using System;
+
+namespace PCL.Neo.Messages;
+
+public class NavigationMessage(
+    ViewModelBase? oldMainViewModel,
+    ViewModelBase? newMainViewModel,
+    ViewModelBase? oldSubViewModel,
+    ViewModelBase? newSubViewModel,
+    NavigationType navigationType)
+{
+    public static class Channels
+    {
+        public static readonly Guid Navigating = Guid.NewGuid();
+        public static readonly Guid Navigated = Guid.NewGuid();
+    }
+
+    public bool           IsMainViewModelChanged => oldMainViewModel != newMainViewModel;
+    public ViewModelBase? OldMainViewModel       => oldMainViewModel;
+    public ViewModelBase? NewMainViewModel       => newMainViewModel;
+    public bool           IsSubViewModelChanged  => oldSubViewModel != newSubViewModel;
+    public ViewModelBase? OldSubViewModel        => oldSubViewModel;
+    public ViewModelBase? NewSubViewModel        => newSubViewModel;
+    public NavigationType NavigationType         => navigationType;
+}