🩹 修复关闭后仍有后台窗口, 优化主窗口动画

Util/RelayCommand.cs

@@ -0,0 +1,37 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.Windows.Input;
+
+namespace GeekDesk.Util
+{
+    public class RelayCommand : ICommand
+    {
+        private readonly Predicate<object> _canExecute;
+        private readonly Action<object> _execute;
+
+        public RelayCommand(Predicate<object> canExecute, Action<object> execute)
+        {
+            _canExecute = canExecute;
+            _execute = execute;
+        }
+
+        public event EventHandler CanExecuteChanged
+        {
+            add => CommandManager.RequerySuggested += value;
+            remove => CommandManager.RequerySuggested -= value;
+        }
+
+        public bool CanExecute(object parameter)
+        {
+            return _canExecute(parameter);
+        }
+
+        public void Execute(object parameter)
+        {
+            _execute(parameter);
+        }
+    }
+}