Delphi禁止运行程序多个实例，程序先初始化参数，然后判断程序是否已经运行，得到程序的句柄，若发现多个句柄，就只运行一个句柄，程序也就始终保持一个窗口。-Delphi is prohibited to run multiple instances of the program, the program first initialization parameters, and then determine whether the program is already running, get a handle on the program, if found multiple handles, run only one handle, the program will always keep a window.