Threading Problem

[Phreak]

Im not completely sure on how to use threads, but I followed a small fairly simple tutorial and what I used and how I used it is below.

PROBLEM: Sometimes the dataset in the FillDataSet() procedure is filled (usually after you run it a second time, usually doesnt ever work the 1st time), and sometimes it doesnt. But I receive NO error of any kind. Maybe Im not using threads correctly. Could anyone give me some input or a better way to use threads?

[These two procedures are taken out of the main form.]

Sorry if its a little long.

    Private Sub OracleConnect()
        Dim dbInfo As New loginInfo()
        Dim frmProgress As New progress()

        t = New Thread(AddressOf Me.FillDataSet)


        If frmLogin.DialogResult = DialogResult.OK Or cmdRefresh = 1 Then

            run the next couple of IFs to handle someone pushing the REFRESH
            button if they arent logged in
            If frmLogin.txtUser.Text = "" Or frmLogin.txtPwd.Text = "" Or frmLogin.txtServer.Text = "" Then
                cmdRefresh = MsgBox("Unable to refresh tables because you are not currently logged on." & _
                             vbCrLf & "Would you like to logon now?", MsgBoxStyle.YesNo, "Refresh Problem")
            End If

            If cmdRefresh = 6 Then
                cmdRefresh = 0
                frmLogin.ShowDialog()
                OracleConnectString(frmLogin.txtUser.Text, frmLogin.txtPwd.Text, frmLogin.txtServer.Text)
                OracleConnect()
                Exit Sub
            ElseIf cmdRefresh = 7 Then
                cmdRefresh = 0
                Exit Sub
            End If

            frmProgress.Timer1.Start()
            t.Start()

            frmProgress.ShowDialog()
            frmProgress.Timer1.Stop()

            clear combobox items
            cmbTables.Items.Clear()
            cmbTables.Items.Add("--None Selected--")

            clear datagrid
            dsSeedList.Clear()
            dsSeedList.Reset()
            DataSet21.Clear()
            DataGrid1.Refresh()
            OleDbConnection1.Close()

            frmProgress.Timer1.Start()
            t.Start()

            frmProgress.ShowDialog()
            frmProgress.Timer1.Stop()

            intTblCnt = DataSet21.USER_TABLES.Rows.Count
            cmbTables.DropDownStyle = ComboBoxStyle.DropDownList

            put avail tables into listbox (combobox)
            For i = 0 To intTblCnt - 1 Step 1
                cmbTables.Items.Add(DataSet21.USER_TABLES.Rows.Item(i).Item(0))
            Next

            If cmbTables.Items.Count > 0 Then
                cmbTables.SelectedItem = cmbTables.Items.Item(0)
            End If

            If connError = 1 Then
                connError = 0
                connError = CType(MsgBox("There was an error while trying to connect to the database." & _
                            "  Would you like to try again?", MsgBoxStyle.YesNo, "Retry Connection?"), Short)
                If connError <> 6 Then
                    connError = 0
                Else
                    frmLogin.ShowDialog()
                    If frmLogin.DialogResult = DialogResult.Cancel Then
                        Exit Sub
                    Else
                        With dbInfo
                            .user = frmLogin.txtUser.Text
                            .pass = frmLogin.txtPwd.Text
                            .serv = frmLogin.txtServer.Text
                        End With

                        Call OracleConnectString(dbInfo.user, dbInfo.pass, dbInfo.serv)
                        Call OracleConnect()
                        ButtonPressed = False
                    End If
                End If
            End If
        End If
        cmdRefresh = 0
        connError = 0
        t.Abort()
        Call CheckForTables()
    End Sub
#End Region

#Region "Fill Table Listing"
    Private Sub FillDataSet()

        Try

            fill the dataset with the list of tables
            OleDbDataAdapter2.Fill(DataSet21, "USER_TABLES")

        Catch ex As System.Exception

            in case an exception is thrown, give an error box and
            a moderate description of where the exception was thrown
            If ex.GetType.ToString = "System.Threading.ThreadAbortException" Then
                do nothing... just ignore it.  its dumb and has no idea what its doing.
            Else
                MsgBox("Error retrieving tables!" & vbCrLf & "Details:" & vbCrLf & "    " & _
                        ex.GetType.ToString & vbCrLf & vbCrLf & "Check your username and password " & _
                        "and make sure they are correct.", MsgBoxStyle.Critical, "Table Retrieval Error")
                connError = 1
            End If
        Finally
            OleDbConnection1.Close()
        End Try
    End Sub
#End Region

 

[Robby]

The way you have it now, it is stateless, you arent getting any feedback on the thread. You will need to check on the ThreadState.
And the t.Abort() is miss-placed.

 

[Phreak]

What do you mean ThreadState? What state am I looking for? And if the t.Abort() is misplaced, where should it go? Like I said, Im not familiar with using threads at all. I just need to use them in this particular occassion because of the time it takes to fill the dataset. Thanks for the reply.

 

[Robby]

I have only worked on Stateless (asynchronous) threading, but as a guess I would try something like this...
this is untested ( let me know if it works)

frmProgress.ShowDialog() 
Do While t.ThreadState = ThreadState.Running

Loop
frmProgress.Timer1.Stop()

and t.Abort() should be used to abort the thread if there is an exception

 

[Phreak]

Yes, it does work. So far I havent had any problems whatsoever. So hopefully this will continue to work and I wont have any more problems. Thanks a ton.