[RESOLVED] [2008] Application Exits Prematurely

[youngbucks]

I have a module that is set to be the "main" thing that loads so it goes through a process of parsing through an XML file but as soon as it is completed the application exits even when i tell it to load the first form :S any ideas why?

[obi1kenobi]

Try debugging the code line by line and see what's going on. That is the best advice I can give you without seeing the code.

[Shaggy Hiker]

So the program starts with a Sub Main? At some point you show the first form. Do you show that form using Show? If so, that's the problem, as Show doesn't block, so the Sub Main will run to the End Sub, at which point your app ends. This was a more common issue in 2003, where everyone used Sub Main by default. The easy way around this is ShowDialog, but that will have other problems, depending on how the code is set up. There is a more complicated solution, but I'll leave it out for now, as I have made enough assumptions so far.

[youngbucks]

This is my module at the moment:

Imports System.IO
Imports System.Xml
Module Module_Main
 
    Sub Main()
        Try
            'Check for the existence of the file before proceeding.
            If Not IO.File.Exists(Application.StartupPath & "/Patch.xml") Then
                MsgBox("Cannot find patch file!")
                Exit Sub
            End If
 
            Dim m_xmlr As XmlTextReader
 
            'create the XML reader
            m_xmlr = New XmlTextReader(Application.StartupPath & "/Patch.xml")
 
            'Disable whitespace so that you don't have to read over whitespaces
            m_xmlr.WhitespaceHandling = WhitespaceHandling.None
 
            'read the xml declaration and advance to family tag
            m_xmlr.Read()
 
            'read the family tag
            m_xmlr.Read()
 
            'Load the Loop
            While Not m_xmlr.EOF
                'Go to the name tag
                m_xmlr.Read()
 
                'if not start element exit while loop
                If Not m_xmlr.IsStartElement() Then
                    Exit While
                End If
 
                'Get the file name attribute
                Dim FILENAMEAttribute = m_xmlr.GetAttribute("filename")
 
                'Read elements Size and Checksum
                m_xmlr.Read()
 
                'Get the SIZE Element 
                Dim SIZEValue = m_xmlr.ReadElementString("SIZE")
 
                'Get the CHECKSUM Element
                Dim CHECKSUMValue = m_xmlr.ReadElementString("CHECKSUM")
 
                'Return Information
                MsgBox("FILENAME: " & FILENAMEAttribute _
                   & " SIZE: " & SIZEValue & " CHECKSUM: " _
                  & CHECKSUMValue)
                ' Console.Write(vbCrLf)
            End While
            'close the reader
            m_xmlr.Close()
        Catch ex As Exception
            MsgBox(ex.ToString)
            Exit Sub
        End Try
        Form1.Show()
    End Sub
End Module

Right now its just parsing an XML file with a loop and getting information. I call Form1.Show() at the end to load the main form for the application but it just exits the app. What can i use to fix this problem in my case?

[dbasnett]

why not just make this a form application and move the code to the form load event?

[youngbucks]

When i use a form for some reason it takes longer (The full patch file contains alot of information) and this is going to be added to a patching process to replace my current one. I want it to check the files first and if it needs patching load the patcher and if it doesnt load the executable for the game.

[Shaggy Hiker]

If all you are going to do is show the one form, then Form1.ShowDialog will solve your problem. Show doesn't block the current execution, and the application ends when Sub Main exits, regardless of whether or not there are other forms being displayed. Therefore, you can't reach the end of Sub Main until you are ready to. ShowDialog will block Sub Main until Form1 is hidden.

This will work as long as Form1 is intended to stay open for the duration of the program. If that is not the case, then you need a slightly more elaborate construct, but if Form1 will remain open for the duration, then the ShowDialog is all you need.

[bluehairman]

Looks like you close the form before you even load the other one? And closing the main startup form will end your application, use .hide

[youngbucks]

Thanks Shaggy Form1.Showdialog() is what i needed because the form will only temporarily show to update then launch the game, thank you

[Shaggy Hiker]

If you close Form1, then ShowDialog won't be enough (unless you load something else immediately afterwards), as closing Form1 will cause ShowDialog to return, at which point Sub Main will exit and the app will terminate.