shell用法详解（Detailed usage shell）.docVIP

shell用法详解（Detailed usage shell） In VB, an external program is often executed with the Shell command, but it is immediately after the external Create of the process Youll go back to the next line of VB, and you cant wait for the Process to end before you execute the next line, Or is it not possible to know whether the Process is finished or even if the Process executes halfway? Suspend execution, etc. These are not controlled by the Shell command, so we need to get APIs help done A. The first question is how to wait for the Create process of shell to end up executing the VB program later. The first thing to know is that each Process has the only one ProcessID, which is given by OS To distinguish each Process, this Process ID (PID) is primarily used to obtain some of the corresponding Process Information, however, is mostly controlled by Process Handle (hProcess) to control the Process. VB The return value of the Shell directive is PID, not hProcess, so we need to go through the OpenProcess, the API HProcess and OpenProcess () the first parameter, is made of hProcess Ability, like PROCESS_QUERY_INFORMATION, is to let GetExitCode () get the hProcess point The state of process, and PROCESS_TERMINATE, is to make TerminateProcess (hProcess..) The command can be effective, that is to say, different parameter setting, the authority, hProcess has some ability Different. After you get hProcess, you can use WaitForSingleObject () to wait for the hProcess state Change, that is, it will wait until hProcess refers to the execution of the process, and that instruction ends Second parameters (WaitForSingleObject) refers to the waiting time (in milliseconds) If you exceed the time indicated, end the WaitForSingleObject () wait for TimeOut. If you want it Wait indefinitely, set to INFINITE. PID = Shell (C:\tools\spe3\pe2.exe, vbNormalFocus) HProcess = OpenProcess (PROCESS_QUERY_INFORMATION, 0, PID) ExitEvent = WaitForSingleObject (hProcess, INFINITE) Call CloseHandle (hProcess) The l