Threading.Timer的疑惑
有下边的一段代码，在button1里启动了Threading.Timer后，发现竟然停止不了了。检测对象时发现Timer对象已经销毁，但getsize()里的代码竟然还在执行。

这个是否有别的问题？

VB.NET code

    Private RemotFile As String = "" '远程文件路径    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click        Dim n As New System.IO.FileInfo(MusicFile.Text)        fileName = MusicFile.Text        FileSize = n.Length        Dim b As New Threading.Thread(AddressOf Upload)        b.IsBackground = True        b.Start()        Dim GetSizeThread As Thread        GetSizeThread = New Threading.Thread(AddressOf TestThreadTimer)        GetSizeThread.IsBackground = True        GetSizeThread.Start()    End Sub    Private ThreadTimer As System.Threading.Timer = Nothing    Public Sub TestThreadTimer()        ThreadTimer = New System.Threading.Timer(New TimerCallback(AddressOf Me.GetSize), Nothing, 0, 200)    End Sub    Private FileSize As Long = 0    Private fileName As String = ""    Private Sub Upload()        Dim ftp As New FTPUpDown        ftp.FtpServerIP = "ftp://www.aaa.com/"        ftp.FtpUserName = "aaa"        ftp.FtpPassword = "aaa"        ftp.Upload(fileName, RemotFile)        Try            Threading.Thread.CurrentThread.Join()        Catch ex As Threading.ThreadAbortException            Err.Clear()        Finally            Threading.Thread.CurrentThread.Abort()        End Try    End Sub    Private Sub GetSize()        Try            Dim a As New FTPUpDown            a.FtpServerIP = "ftp://www.aaa.com/"            a.FtpUserName = "aaa"            a.FtpPassword = "aaa"            Dim t As Long = a.GetFileSize(RemotFile)            SetText(Status, ((t / FileSize) * 100).ToString("00.00") & "%" & Now)            SetPro(FileSize, t)            If t >= FileSize Then                If Not ThreadTimer Is Nothing Then                    ThreadTimer.Dispose()                    ThreadTimer = Nothing                End If            End If            Threading.Thread.CurrentThread.Join()        Catch ex As Threading.ThreadAbortException            Err.Clear()        Finally            Threading.Thread.CurrentThread.Abort()        End Try    End Sub    Delegate Sub SetProV(ByVal m As Integer, ByVal v As Integer)    Private Sub SetPro(ByVal m As Integer, ByVal v As Integer)        If Me.ProgressBar1.InvokeRequired Then            Dim d As New SetProV(AddressOf SetPro)            Me.Invoke(d, New Object() {m, v})        Else            ProgressBar1.Maximum = m            ProgressBar1.Value = v        End If    End Sub    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click        If Not ThreadTimer Is Nothing Then            ThreadTimer.Dispose()            ThreadTimer = Nothing        End If        Dim a As New FTPUpDown        a.FtpServerIP = "ftp://www.aaa.com/"        a.FtpUserName = "aaa"        a.FtpPassword = "aaa"        Dim b As New Thread(AddressOf DeleteFile)        b.IsBackground = True        b.Start()    End Sub    Private Sub DeleteFile()        Dim a As New FTPUpDown        a.FtpServerIP = "ftp://www.aaa.com/"        a.FtpUserName = "aaa"        a.FtpPassword = "aaa"        If a.Delete(RemotFile) = True Then            SetText(Status, "Finished!")        Else            SetText(Status, "Failed.")        End If        Try            Threading.Thread.CurrentThread.Join()        Catch ex As Threading.ThreadAbortException            Err.Clear()        Finally            Threading.Thread.CurrentThread.Abort()        End Try    End Sub

Threading.Timer只执行了一次
http://www.cnblogs.com/shang20017/archive/2009/03/16/1413798.html
[解决办法]
不奇怪，实践证明Abort并不能保证线程一定被终止，所以我经常在程序结束时才Abort，就这样也不可靠，所以对于带线程的程序，结束时除了me.close外，还要把application.exit以及久违的End一鼓脑全加上