这个函数是用来处理串口消息事件的，如每当串口接收到数据，就会产生一个串口接收数据缓冲区中有字符的消息事件，我们刚才添加的函数就会执行，我们在OnComm()函数加入相应的处理代码就能实现自已想要的功能了。-this function is used to handle serial news events, whenever serial data received, will have a serial port receiving data buffer characters are news events, we have just added function will be implemented, We OnComm () function corresponding to the handling code can achieve their own desired functions.