[02/03] Threading and Web Exception

[JohnRChick]

Hey. I have a question on aborting a thread and error messages here. I have a thread that is used to do the following: creates a temporary directory on the c:\ drive, checks to see if a text file is available on my server, and downloads it if available. What I've created here is an updating system for my program basically. I have a STOP button that lets the user stop the process and close the updating forum. Here's some of my code:

Private Sub startUpdating()
 
        ButtonForceUpdate.Visible = False
 
        If findPaths() = True Then
            If findDefinitions() = True Then
                If downloadDefinitions() = True Then
                    startUIThread = True 'used to tell UI thread that it can check versions now
                    'must now use timer to check instead of using delegate code
                Else
                    Me.Close()
                End If
            Else
                Me.Close()
            End If
        Else
            Me.Close()
        End If
 
    End Sub
 
    Private Function findPaths() 'finds temp download paths
        LabelChecking.Text = "Creating Temporary Directories..."
 
        Try
                IO.Directory.CreateDirectory("C:\tempupdater")
                tempDIR = "C:\tempupdater"
            
            Return True
        Catch ex As Exception
            MsgBox(ex.Message)
            Return False
        End Try
    End Function
 
    Private Function findDefinitions() 'find definitions on server
        LabelChecking.Text = "Locating Definitions on Server..."
        Try
            wc.OpenRead("http://www.myserver.com/version.txt")
            Return True
 
        Catch ex As Exception 'cant find definition
            If MsgBox("The definition files couldn't be found on the server. Would you like to try again?", MsgBoxStyle.YesNo) = MsgBoxResult.Yes Then
                findDefinitions() 'try again if click yes
            Else
                Return False
            End If
        End Try
 
Private Function downloadDefinitions()
        LabelChecking.Text = "Downloading Definitions..."
        Try
            wc.DownloadFile("http://www.myserver.com/version.txt", tempDIR & "definitions.txt")
            Return True
        Catch ex As Exception
            If MsgBox("An error occured while downloading definitions. The following error was returned:" & vbNewLine & vbNewLine & ex.Message & vbNewLine & vbNewLine & " Would you like to try and download again?", MsgBoxStyle.YesNo) = MsgBoxResult.Yes Then
                downloadDefinitions()
            Else
                Return False
            End If
 
        End Try
    End Function
 
Private Sub formUpdate_Closing(ByVal sender As Object, ByVal ByVale As System.ComponentModel.CancelEventArgs) Handles MyBase.Closing
        Try
            IO.File.Delete(tempDIR & "definitions.txt")
            IO.Directory.Delete(tempDIR, True)
        Catch ex As Exception
 
        End Try
 
        startUpdatingThread.Abort()
        Me.Dispose()
        fu = Nothing
    End Function

ok so that's basically all my code that's in a thread. I apologize in advance, because I'm new to programming so it might not be correct. Ok the problem is that when the user wants to stop updating, then it will give me an error. For example if the user is currently in the stage for downloading the definitions, it will throw the exception there about not being able to download them. So it actually confuses the user because they clicked stop. How can I make it so that it will just stop with no errors and what not? Any ideas?

Thanks
John

[JohnRChick]

anyone?

[-TPM-]

How are you cloasing the thread? Just thread.abourt?

[JohnRChick]

yes like in the .closing method for the forum. Is it not good programming practice to abort a thread when it's not done or something? That's basicalyl what I'm trying to do. Just stop the thread when the forum is done and it should stop everything in the background; but I end up getting an exception in whichever method the thread is currently running.