添加项目文件。

Szmedi.Test/SingletonWindowManager.cs

@@ -0,0 +1,41 @@
+using System;
+using System.Windows;
+using System.Windows.Interop;
+
+
+namespace Szmedi.Test
+{
+    public static class SingletonWindowManager
+    {
+        private static Window _currentWindow;
+
+        public static void ShowOrActivate<TWindow, TViewModel>(params object[] viewModelParameters)
+            where TWindow : Window, new()
+            where TViewModel : class
+        {
+            if (_currentWindow == null || _currentWindow is not TWindow)
+            {
+                _currentWindow?.Close();
+                _currentWindow = new TWindow();
+                if (_currentWindow.DataContext == null || _currentWindow.DataContext is not TViewModel)
+                {
+                    if (viewModelParameters.Length == 0)
+                    {
+                        _currentWindow.DataContext = Activator.CreateInstance(typeof(TViewModel));
+                    }
+                    else
+                    {
+                        _currentWindow.DataContext = Activator.CreateInstance(typeof(TViewModel), viewModelParameters);
+                    }
+                }
+                _currentWindow.Closed += (sender, args) => _currentWindow = null;
+                _ = new WindowInteropHelper(_currentWindow) { Owner = System.Diagnostics.Process.GetCurrentProcess().MainWindowHandle };
+                _currentWindow.Show();
+            }
+            else
+            {
+                _currentWindow.Activate();
+            }
+        }
+    }
+}