加载界面、程序关闭界面、单例模式

DHSoftware/LoginWindow.cs

@@ -17,7 +17,19 @@ namespace DHSoftware
             button_cancel.Click += Button_cancel_Click;
 
         }
-
+        /// <summary>
+        /// 窗体对象实例
+        /// </summary>
+        private static LoginWindow _instance;
+        internal static LoginWindow Instance
+        {
+            get
+            {
+                if (_instance == null)
+                    _instance = new LoginWindow();
+                return _instance;
+            }
+        }
         private void Button_cancel_Click(object? sender, EventArgs e)
         {
             this.Dispose();