判断窗体的状态，是模式窗体还是非模式窗体，原来是帮一个人写的，也不知道是否准确，请大家帮忙鉴定，还有没有好的方法呢。-Determine the form of the state, is modal or non-modal form, was originally written to help a person, do not know whether it is accurate, please help us to identify, there is no good way to d