Odd Threading Issue...

[thoffman]

Hello all -

I am experiencing an extremely odd bug with an application I've created and I cannot figure out why it is doing this...

The application generates weekly reporting stats as Excel files by copying the previous week's file with a new name (ex: 04-06-2009.xls - Monday of the week the stats will be generated for), clears the data within the workbook and inserts the selected week's stats that are pulled from raw data extracts.

This portion of the form contains a date/time picker with the initial value of March 18, 2009, a label, a text box and a button to browse for files if a previous stats file needs to be rebuilt. The date/time picker obviously allows for the user to choose a date for the new file. On the DTP value changed event, it locates the previous week's file and inserts the file path into the label as it's text, generates the new file name and sets the textbox text to that file name.

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Try
            Control.CheckForIllegalCrossThreadCalls = False
 
            ' Set the date for the dtpWeeklyExportDate date chooser
            Me.dtpWeeklyExportDate.Value = Date.Today.ToShortDateString()
        Catch ex As Exception
            Me.ToolStripStatusLabel1.Text = ex.Message
        End Try
    End Sub
 
Private Sub ExecuteImportToolStripMenuItem1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ExecuteImportToolStripMenuItem1.Click
    Progress.ShowDialog()
End Sub
 
Private Sub Progress_Shown(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Shown
    Dim strSource As String = Form1.lblWeeklyExportFile.Text
    Dim strDest As String = strSource.Substring(0, Form1.lblWeeklyExportFile.Text.LastIndexOf("\") + 1) & Form1.txtWeeklyNewFileName.Text
    File.Copy(strSource, strDest, True)
End Sub
 

The problem is that as soon as the background worker is called, the strDest defaults to the first "Monday" value that was originally assigned to the textbox during the application initialization, which is pulled from the March 18th value assigned in design mode rather than the current text value...

Any help would be greatly appreciated!

-Tyler

[thoffman]

Update:

I altered the code so that the File.Copy() method is not being handled by the background worker but is handled by the Progress.Shown() method and it works as it is supposed to... So the problem is that the thread is somehow grabbing what the text box was first assigned... I have no idea why it is doing this but I'm sure it's a memory bug or something... Help please?

[thoffman]

Well it's fixed for those who viewed and decided that they needed to know how... It must have been a memory issue or something but I still don't know why this happened...

As the progress dialogbox initiates, I assigned the current textbox value from the parent thread to a form specific first child thread's public variable during the Progress.Activated() subroutine, which maintains that value for the progress' child thread to reference to; since it's now operating within it's "own" thread and not two threads away, everything works like a charm... Why it referred back to an older value from the parent's parent thread (even though it was supposed to have been over written in the same block of memory is unknown to me), I don't know...

In conclusion, I believe it would be best if I picked up a book that specifically outlines multi-threading (NOT produced by Microsoft as this is where my debugging issues began and they didn't know why or how to fix it either even though I followed their "logical" examples to begin with). Outsourcing SUCKS!