实现mfc单文档视图分割与切换，通过按钮来切换分割视图与为分割视图。-To achieve a single view of the document segmentation and mfc switch of a button to switch to split view and split view.

视图切换，通过视图分割的方法来进行视图切换的，此方法已得到验证-View Switch，View to split view switching, this method has been validated