孙鑫教学第七课全内容，包括SDI中调用对话框， 创建非模态对话框，为静态文本框增加消息响应，以及回车时将输入焦点移动到下一个控件-Sun Xin teaching the whole content of seventh courses, including the SDI call dialog box, create a non modal dialog box, for the static text box to increase the message response, as wel