> Given the following code I am wondering if SyncLock is required.  Because I
> am using system.timer is there already this type of lock behaviour in place?
> I need to assure that I'm only selecting one distinct record at a time per
> thread...
>
> Public Class Form1
>
>    Private MessageArray() As MessageHandler
>    Private MH As MessageHandler
>
>    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As
> System.EventArgs) Handles MyBase.Load
>
>        MH = New MessageHandler
>
>        Dim i As Integer
>        Dim iTo As Integer = 4  '4 threads
>        Dim iFrom As Integer = 1
>
>        ReDim MessageArray(iTo - iFrom)
>        Dim Msg As MessageHandler
>        For i = iFrom To iTo
>            Msg = New MessageHandler()
>            MessageArray(i - iFrom) = Msg
>            'pass parameters to the new thread
>            Msg.i = i
>            Msg.MainForm = Me
>            Dim ts As ThreadStart
>            ts = New ThreadStart(AddressOf Msg.ProcessingOutboundThread)
>            Dim wrkThread As Thread
>            wrkThread = New Thread(ts)
>            Msg.CurrentThread = wrkThread
>            wrkThread.SetApartmentState(ApartmentState.STA)
>            wrkThread.Name = i.ToString() 'for easier tracing
>            wrkThread.Start()
>        Next
>        'end start
>    End Sub
>
> End Class
>
> Class MessageHandler
>
>    Public MainForm As Form1
>    Public i As Integer
>    Public CurrentThread As Thread
>    Public iThreadId As Integer
>    Public cnString As String =
> "server=servername;database=dbname;uid=username;pwd=password"
>    Private WithEvents Timer1 As System.Timers.Timer
>
>    Private Sub Timer1_Elapsed(ByVal sender As Object, ByVal e As
> System.Timers.ElapsedEventArgs) Handles Timer1.Elapsed
>
>        iThreadId = Thread.CurrentThread.GetHashCode()
>
>        Dim cn As SqlConnection
>        cn = New SqlConnection(cnString)
>        Dim cmd As SqlCommand
>        Dim dtr As SqlDataReader
>
>        Try
>           Try
>                cmd = New SqlCommand("select top 1 * from queue_table where
> time_to_send=1", cn)
>                cn.Open()
>                    dtr = cmd.ExecuteReader()
>                    If dtr.HasRows() = True Then
>                        dtr.Read()
>                        Dim varE As String = dtr("employeetosendto")
>                        Dim varM As String = dtr("employeemessageaddress")
>                        dtr.Close()
>                        cmd = New SqlCommand("update queue_table set
> time_to_send=0 where employee='" & varE & "'", cn)
>                        cmd.ExecuteNonQuery()
> Call_Send_Message_Sub_Here 'call another sub pass employeemessageadress as
> param
>                        cmd = New SqlCommand("update queue_table set
> sentmessage=1 where employee='" & varE & "'", cn)
>                        cmd.ExecuteNonQuery()
>     end if
>                Catch ex As Exception
>                    msgbox(ex.Message.ToString())
>                Finally
>                    If cn.State = ConnectionState.Open Then cn.Close()
>                End Try
>            End If
>        Catch ex As Exception
>               msgbox(ex.Message.ToString())
>        Finally
>            If cn.State = ConnectionState.Open Then cn.Close()
>        End Try
>    End Sub
>
>    Public Sub ProcessingOutboundThread()
>        Dim iThreadId As Integer
>        iThreadId = Thread.CurrentThread.GetHashCode()
>
>        Timer1 = New System.Timers.Timer
>        Timer1.Interval = 5000 ' 5 seconds
>        Timer1.Start()
>
>        Application.Run()
>    End Sub
> End Class
>
> I'd appreciate any feedback on how I can make this a more threadsafe app or
> more stable app.  Thanks a lot.
>
> Jay