Can not get Process to die in VB.net

Question

I've inherited some VB.net code. My task is to find out why it isn't working. I have 2 applications. The first one

is run as a service, infinitely checking a table to see if there are any tasks to be handled. If it finds one, its supposed to fire off the second application to handle the task then returns to the loop and checks for another. Both these applications are forms but they do not show any windows. The problem I'm having is after the second application is finished, the first application never gets a signal it is done so it is waiting forever, thus it can't move onto the next task. If I go into TaskManager and kill the second application, the first one gets that notification and proceeds as it should. Below is how I am creating the process and waiting for it. I've tried several different ways of creating and waiting for the process (using a Shell/OpenProcess, WaitForSingleObject,etc) and I can't get it to work. I've searched all over the internet, StackOverflow and the MSDN site but nothing I've tried works. I've been messing with this for 2 days!!

Form 1 Load:

Dim ProcessProperties As New ProcessStartInfo
ProcessProperties.FileName = strExeFullPath
ProcessProperties.Arguments = " /project " & l_project 
ProcessProperties.CreateNoWindow = True
Dim myProcess As Process = Process.Start(ProcessProperties)
myProcess.WaitForExit()

When Form2 is finished, it does a Me.Close() and Exit Sub in the load subroutine but the process is still showing in the TaskManager and never returns to Form1 so Form1 is in WaitForExit forever. I've tried closing every open file and connection and setting them to Nothing in Form2, Me.Dispose,etc. I've tried Application.Exit as the last line of Form2. That stupid thing will not die!! Why won't it DIE!!??!!

What am I missing?

Answer 1

If I go into TaskManager and kill the second application, the first one gets that notification

Keep your eyes on the ball, the real problem is that this second application is not exiting by itself. And thus myProcess.WaitForExit() isn't going to return. So this is not a problem in your code snippet.

Why the 2nd app doesn't want to quit is completely unclear from your question. Given that it is a Windows Forms app, do keep in mind that there is nobody to click the Close button of the form. Application.Exit() should make it stop, Environment.Exit() is a rude abort that cannot be veto-ed by a FormClosing event handler.

Answer 2

Anyway use this:

ProcessProperties.Arguments = String.Format("/project {0}", 1_project)

No leading space is required and code becomes more readable.

Cheers!

Answer 3

I suspect Form2 is trying to show some modal dialog (maybe a message box, maybe an unhandled exception box) before quitting. Since App2 is launched by App1, which is a service, Form2 cannot interact with the desktop and just sits there waiting for a button click that will never happen.

Try to allow the App1 service to interact with the desktop (you can find that option on the Log On tab of the service properties dialog box) and check if Form2 actually pops up a dialog before quitting.