VB.Net多线程-事件未触发？

Question

I've got this code, and let's say I am iterating over 100 items. The first time I iterate over the list, the ProxyTested event fires 100 times. Great, that was easy.

Now comes the annoying unknown bug currently giving me a headache, if only it would give me an exception too, then I could probably figure out whats going wrong much easier.

Here it is: The second time I iterate over the list, and each time after, the ProxyTested event fires 99 times. What happened to 1 of my iterations?

PS For my project, Tasks throughput is much slower than spawning say 500 of my own threads, so because of that reason I don't want to use them. Just saying that before the inevitable suggestion. It may not look so pretty, but it runs very, very fast compared to creating a list of Tasks and passing them into Task.WaitAll, which is admittedly much easier on the eyes.

PSS Also, before the use a Concurrent Collection suggestion that is also inevitable, need to use a DataTable here, because I am also using SqliteDataAdapter.Update in this project, which only takes a DataTable or array of DataRow's.

Dim counter as integer = 0
For i = 0 To ThreadCount - 1
            Dim t As New Thread(Sub()
                                Do

                                    Dim item As DataRow = Nothing
                                    Dim req As HttpWebRequest = Nothing
                                    SyncLock lock
                                        If counter > Proxies.Rows.Count Then
                                            Exit Do
                                        End If
                                        item = Proxies(counter)
                                        Interlocked.Increment(counter)
                                        Dim judge As DataRow = validJudges(rnd.Next(0, validJudges.Count))
                                        Dim proxy As String = item("ip") & ":" & item("port")

                                        req = HttpWebRequest.Create(judge("url"))
                                        req.Proxy = New WebProxy(proxy)
                                        req.Timeout = Timeout
                                        Debug.WriteLine(counter)
                                    End SyncLock

                                    Dim statusText As String = ProxyTest.GetStatus(req, "<title>AZ Environment variables 1.04</title>", externalIp)

                                    SyncLock lock
                                        item("statusText") = statusText

                                        If statusText = "Valid" Then
                                            Interlocked.Increment(ValidCount)
                                        Else
                                            Interlocked.Increment(InvalidCount)
                                        End If
                                        Interlocked.Increment(CompletedCount)
                                        RaiseEvent ProxyTested(item)
                                    End SyncLock

                                Loop
                                mre.Set()
                            End Sub)
            t.Start()
        Next
        mre.Reset()
        mre.WaitOne()

Answer 1

Re initializing my ManualResetEvent each time I called this method solved my problem :)

mre = New ManualResetEvent(False)

Previously mre was a global that was only initialized once during loading.