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Thread with an Icon.Save command  cannot be ended by Scheduled Task "End Task" option.

MikeBroderick
on
Medium Priority
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Last Modified: 2010-04-30
I have a VB.Net console application that issues an Icon.Save command to a memory stream. I defined a Scheduled task to process it. I issue start and stop commands from the Scheduled Tasks menu.

When I issue the end task, the status on the Scheduled Task display goes from "Running" to blank. However, from the Task Manager display the process is still there. The main task is still running; I put an Event log display in to verify it.

The problem occurs on 2 XP/Pro SP 2 (current) machines. A W/2000 server machine does not have the problem. The code was compiled with VS 2003. Here is a sample program to illustrate:

Imports System.Threading
Imports System.Drawing
Imports System.IO

Module Module1

    Dim Thr1 As Thread
    Dim stream As New MemoryStream
    Dim tIcon As New Icon("C:\Mike\OffStor\Icons\BackupSet\BackupSet.ico")

    Sub Main()

        Thr1 = New Thread(AddressOf Thr1Sub)
        Thr1.IsBackground = False
        Thr1.Start()

        While True
            Thread.Sleep(5000)
        End While

    End Sub

    Private Sub Thr1Sub()

        tIcon.Save(Stream)

    End Sub

 
End Module
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Mike TomlinsonHigh School Computer Science, Computer Applications, Digital Design, and Mathematics Teacher
CERTIFIED EXPERT
Top Expert 2009

Commented:
What exactly are you trying to achieve with this code?

This part:

        While True
            Thread.Sleep(5000)
        End While

causes an infinite loop and an unrepsonsive app due to the Sleep() call.

Give us the big picture...

Author

Commented:
This is huge simplification of the application. The main task is a tcp listener task that processes incoming commands. The sub task does lots of stuff then ends. it receives the name of a file to process, retrieves the associated icon for that file, then convert the icon into a base 64 string for further processing. I removed all of that because none of it causes the problem.
Mike TomlinsonHigh School Computer Science, Computer Applications, Digital Design, and Mathematics Teacher
CERTIFIED EXPERT
Top Expert 2009

Commented:
Well, the only thing that pops out is the IsBackground() setting of False:

    Thr1.IsBackground = False

From:
http://msdn2.microsoft.com/en-gb/library/system.threading.thread.isbackground.aspx

    "A thread is either a background thread or a foreground thread. Background threads are identical to foreground threads, except that background threads do not prevent a process from terminating. Once all foreground threads belonging to a process have terminated, the common language runtime ends the process. Any remaining background threads are stopped and do not complete."

Since it is NOT a background thread the app is waiting for it to complete before ending...

Author

Commented:
I'm sorry. Just for grins I changed that to False to see if it would work (grasping at straws) and forgot to change it back. True fails also.

I think the sub task is ending OK, it executes to end. If I comment out the icon.save command, I dont have the problem.

Is there any (efficient) way to search Microsoft for known problems, or to report the problem without paying 99 dollars for a support charge?
Mike TomlinsonHigh School Computer Science, Computer Applications, Digital Design, and Mathematics Teacher
CERTIFIED EXPERT
Top Expert 2009

Commented:
Are you actually using some kind of loop to keep your main task alive?

        While True
            Thread.Sleep(5000)
        End While

Look at inheriting from the ApplicationContext() class instead:
http://msdn2.microsoft.com/en-US/library/system.windows.forms.applicationcontext.aspx

A simple example:

Module Module1

    Public Sub Main()
        Application.Run(New MyContext)
    End Sub

    Public Class MyContext
        Inherits ApplicationContext

        Private Thr1 As Thread
        Private stream As New MemoryStream
        Private tIcon As New Icon("C:\Mike\OffStor\Icons\BackupSet\BackupSet.ico")

        Public Sub New()
            Thr1 = New Thread(AddressOf Thr1Sub)
            Thr1.IsBackground = True
            Thr1.Start()
        End Sub

        Private Sub Thr1Sub()
            tIcon.Save(Stream)
        End Sub

    End Class

End Module

Author

Commented:
Just gave it a shot. Same error.

High School Computer Science, Computer Applications, Digital Design, and Mathematics Teacher
CERTIFIED EXPERT
Top Expert 2009
Commented:
I'm outa suggestions then...  =(

The problem lies in the Icon.Save() method.

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Author

Commented:
Thats what I came to conclude. I dont have to fix this (not enough to spend 100 dollars to ask Microsoft). Do you know of any way to check with Microsoft on known bugs with XP (it works on 2000)?
Mike TomlinsonHigh School Computer Science, Computer Applications, Digital Design, and Mathematics Teacher
CERTIFIED EXPERT
Top Expert 2009

Commented:
I'm not sure how to report bugs.

I just do searches on the msdn site:
http://msdn2.microsoft.com/en-us/default.aspx
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