增加ViewModelBase 生命周期控制View

Tests/Store.Management.App.SmokeTests/Program.cs

@@ -58,8 +58,46 @@ class Program
             Console.WriteLine("PASS: LoginViewModel -> ILoginService -> AuthApi, retry, password contract and cancellation.");
             return 0;
         }
-        App app = args.Contains("--status-bar") ? new App() : new TestApp(client);
+        App app = args.Contains("--status-bar") || args.Contains("--view-lifecycle") ? new App() : new TestApp(client);
         app.InitializeComponent();
+        if (args.Contains("--view-lifecycle"))
+        {
+            app.ShutdownMode = ShutdownMode.OnExplicitShutdown;
+            var pageVm = new LifecycleProbe();
+            var windowVm = new LifecycleProbe();
+            var page = new UserControl { DataContext = pageVm, Content = new UserControl() };
+            var window = new Window { DataContext = windowVm, Content = page };
+            window.Show();
+            app.Dispatcher.Invoke(() => { }, DispatcherPriority.ApplicationIdle);
+            Check(pageVm.Loads == 1 && windowVm.Loads == 1, $"窗口和页面各加载一次：{windowVm.Loads}/{pageVm.Loads}");
+            window.Content = null;
+            app.Dispatcher.Invoke(() => { }, DispatcherPriority.ApplicationIdle);
+            Check(pageVm.Unloads == 1, "移出页面触发卸载");
+            window.Content = page;
+            app.Dispatcher.Invoke(() => { }, DispatcherPriority.ApplicationIdle);
+            Check(pageVm.Loads == 2, "重新加入页面再次加载");
+            var replacement = new LifecycleProbe();
+            page.DataContext = replacement;
+            Check(pageVm.Unloads == 2 && replacement.Loads == 1, "已加载的页面更换 ViewModel 后转移通知");
+            windowVm.CancelClose = true;
+            window.Close();
+            Check(window.IsVisible && windowVm.Closes == 0, "ViewModel 可以取消关闭");
+            windowVm.CancelClose = false;
+            window.Close();
+            Check(windowVm.Closes == 1, "窗口关闭后通知 ViewModel");
+            var dialogVm = new LifecycleProbe();
+            var dialog = new DialogWindow
+            {
+                DataContext = dialogVm,
+                Content = new UserControl { DataContext = dialogVm }
+            };
+            dialog.Show();
+            app.Dispatcher.Invoke(() => { }, DispatcherPriority.ApplicationIdle);
+            Check(dialogVm.Loads == 1, "Prism 弹窗宿主和内容共享 ViewModel 时只加载一次");
+            dialog.Close();
+            Console.WriteLine("PASS: view and window lifecycle.");
+            return 0;
+        }
         int exitCode = 0;
         app.Dispatcher.BeginInvoke(DispatcherPriority.ApplicationIdle, new Action(async () =>
         {
@@ -227,6 +265,18 @@ class Program
     static void Check(bool success, string message) { if (!success) throw new Exception(message); }
 }
 
+sealed class LifecycleProbe : ViewModelBase
+{
+    public int Loads { get; private set; }
+    public int Unloads { get; private set; }
+    public int Closes { get; private set; }
+    public bool CancelClose { get; set; }
+    protected override void OnLoaded() => Loads++;
+    protected override void OnUnloaded() => Unloads++;
+    protected override void OnClosing(System.ComponentModel.CancelEventArgs e) => e.Cancel = CancelClose;
+    protected override void OnClosed() => Closes++;
+}
+
 sealed class LoginHandler : HttpMessageHandler
 {
     public int RequestCount { get; private set; }