一组可以用来动态创建UI的类。该代码是集中于一个空闲池使用管理器的CWnd继承控件，该管理器可以帮助我们减少在特定UI场景中GDI资源的使用-One group can be used to dynamically create a UI class. The code is focused on the use of a free pool Manager CWnd inherited control, the manager can help us to reduce the UI in a particular scene GDI resource use