添加demo项目

添加demo项目

Co-Authored-By: NaBian <836904362@qq.com>

HandyControlDemo/App.xaml.cs

@@ -0,0 +1,9 @@
+namespace HandyControlDemo
+{
+    /// <summary>
+    /// App.xaml 的交互逻辑
+    /// </summary>
+    public partial class App
+    {
+    }
+}