使SDI程序窗口启动后立即最大化，在程序的同时就最大化显示，这个功能挺实用，特别是在一些中大型的管理系统中，这个功能挺实用的，用户不需要自己去点击窗口的最大化按钮，窗口即自动最大化显示了。-The SDI program window immediately after startup to maximize the program at the same time maximize the display, this feature is very useful, especially in some of the large-scale management system, this function is very useful, users do not need to click on the window. of the button, the window is automatically maximized display.