整理代码

ShrlAlgoToolkit.RevitAddins/Assists/SingletonViewAssist.cs

@@ -0,0 +1,37 @@
+using System.Windows;
+
+using ShrlAlgoToolkit.Core.Assists;
+using ShrlAlgoToolkit;
+using ShrlAlgoToolkit.Core;
+
+namespace ShrlAlgoToolkit.RevitAddins.Assists;
+
+public sealed record SingletonViewAssist<T>
+    where T : Window, new()
+{
+    private static T _instance;
+    private static readonly object Padlock = new();
+
+    private SingletonViewAssist() { }
+
+    public static T GetInstance(out bool isNewCreate)
+    {
+        isNewCreate = false;
+        //double-check locking
+        if (_instance == null)
+        {
+            isNewCreate = true;
+            lock (Padlock)
+            {
+                _instance ??= new T();
+                _instance.Closed += OnWindowClosed;
+            }
+        }
+        return _instance;
+    }
+
+    private static void OnWindowClosed(object sender, EventArgs e)
+    {
+        _instance = null;
+    }
+}