Run Another Program and Pause Until It’s Done
From within your application, you sometimes need to run another Windows application, or a DOS batch file or utility program that requires some time to do its job. You’d like your Access application to pause until this other program has finished its work. Every time you try it, though, the code starts up the other application but then keeps on going. Is there a way to make Access wait until the other application has completed before moving on?
The Shell function in VBA (and the ShellExecute function we will mention in Section 11.7.2 ) returns a unique long integer value representing the running task. You can use this value—the instance handle for the running application—to track the state of the application. Given an instance handle, you can use the OpenProcess API function to retrieve the process handle for the process. Armed with that process handle, you can then call the GetExitCodeProcess function continually until it sees that the process has shut down. Because this happens automatically once a DOS application has finished running, you can use this technique to wait until a DOS window has closed before moving on in your application.
The sample form in
11-05.MDB, frmTestWait, allows you to try starting both a DOS application and a Windows application, and wait for either to complete. There’s also a button that allows you to start a DOS application but continue the attached code. In each of these cases, the sample ...