support for .NET framework 3.5

Still have bugs

Net35/HandyControlDemo_Net35/Data/Model/DemoDataModel.cs

@@ -0,0 +1,22 @@
+using System.Collections.Generic;
+
+
+namespace HandyControlDemo.Data
+{
+    public class DemoDataModel
+    {
+        public int Index { get; set; }
+
+        public string Name { get; set; }
+
+        public bool IsSelected { get; set; }
+
+        public string Remark { get; set; }
+
+        public DemoType Type { get; set; }
+
+        public string ImgPath { get; set; }
+
+        public List<DemoDataModel> DataList { get; set; }
+    }
+}