1時間ごとにサーバーから新しいアップロードファイルをダウンロードするvb.net Windowsサービスを作成する

Question

ローカルコンピュータに1分ごとにサーバーから新しいアップロードファイルをダウンロードするためのvb.net Windowsサービスを作成するのに役立つ必要があります。このコードは、サービスが開始されても同じファイルをダウンロードしますが、タイマーはここでは機能しません。

サーバにアップロードされた新しいファイルを検出してダウンロードし、毎分タイマーが新しいファイルを定期的にチェックする必要があります。以下は私のコードです。親切に私を助けてください。

コード：

Imports System  
Imports System.IO  
Imports System.Threading  
Imports System.Net  
Imports System.Threading.Timer 

Public Class Service1 

    Dim MyThread As Threading.Thread 
    Protected Overrides Sub OnStart(ByVal args() As String) 
     Try 
      Timer2.Enabled = True 
      MyThread = New Threading.Thread(AddressOf FTPDownloadFile) 
      MyThread.Start() 
      AddHandler Timer2.Tick, AddressOf Timer2_Tick 
      Timer2.Interval = 60000 ' 1 minute time interval 
      Timer2.Start() 
     Catch ex As Exception 
      MsgBox(ex.Message) 
     End Try 
    End Sub  

Protected Overrides Sub OnStop() 

     ' Add code here to perform any tear-down necessary to stop your service. 

     Timer2.Enabled = False 
     MyThread.Abort() 

    End Sub 

    Private Sub FTPDownloadFile() 
     Dim ftpuri As String = "" 
     Dim downloadpath As String = "" 
     Dim ftpusername As String = "" 
     Dim ftppassword As String = "" 

     'Create a WebClient. 
     Dim request As New WebClient() 

     ' Confirm the Network credentials based on the user name and password passed in. 
     request.Credentials = New NetworkCredential("abc", "1234") 

     'Read the file data into a Byte array 
     Dim bytes() As Byte = request.DownloadData("http://iba-iet.netai.net/wordpress/home-2") 



     Try 
      ' Create a FileStream to read the file into 
      Dim DownloadStream As FileStream = IO.File.Create("C:\file.html") 
      ' Stream this data into the file 
      DownloadStream.Write(bytes, 0, bytes.Length) 
      ' Close the FileStream 
      DownloadStream.Close() 

     Catch ex As Exception 
      MsgBox(ex.Message) 
      Exit Sub 
     End Try 

     MsgBox("Process Complete") 

    End Sub 

    Private Sub Timer2_Tick(sender As Object, e As EventArgs) Handles Timer2.Tick 
     Try 
      FTPDownloadFile() 
      Timer2.Stop() 
     Catch ex As Exception 
     Finally 
      Timer2.Start() 
     End Try 
    End Sub 
End Class 

Answer 1

Imports System 
Imports System.IO 
Imports System.Net 
Imports System.Timers 
Imports System.Threading 

Public Class Service1 
Dim _oTimer As New System.Timers.Timer() 
Dim _shutdownEvent As New ManualResetEvent(False) 
Dim _processEvent As New ManualResetEvent(False) 
Dim _thread As Thread 
Protected Overrides Sub OnStart(ByVal args() As String) 

    'Setting Thread and Timmer to Pool for jobs 
    _thread = New Thread(AddressOf Execute) 
    _thread.IsBackground = False 
    _thread.Start() 
    AddHandler _oTimer.Elapsed, Function(sender, e) _processEvent.[Set]() 
    _oTimer.AutoReset = False 
    _oTimer.Interval = 10000 
    _oTimer.Enabled = True 

End Sub 

Protected Overrides Sub OnStop() 
    _shutdownEvent.[Set]() 
    _thread.Join() 
    _oTimer.[Stop]() 
    _oTimer.Dispose() 
End Sub 

Private Sub Execute() 
    Dim [handles] = New WaitHandle() {_shutdownEvent, _processEvent} 
    Try 
     While Not _shutdownEvent.WaitOne(0) 
      Select Case WaitHandle.WaitAny([handles]) 
       Case 0 ' Shutdown Event 
        Exit Select 
       Case 1 
        FTPDownloadFile() 
        _processEvent.Reset() ' reset for next time 
        _oTimer.Start() ' trigger timer again 
        Exit Select 
      End Select 
     End While 
    Catch ex As Exception 
    End Try 
End Sub 

Private Sub FTPDownloadFile() 
    Dim FTPUri As String = "ftp://mywebsite.com/" 
    Dim FTPUser As String = "abc" 
    Dim FTPPwd As String = "123" 
    Dim LocalPath As String = "C:\Myfolder\" 

    Dim request As FtpWebRequest = DirectCast(WebRequest.Create(FTPUri), FtpWebRequest) 
    request.Method = WebRequestMethods.Ftp.ListDirectory 
    request.Credentials = New NetworkCredential(FTPUser, FTPPwd) 
    Dim response As FtpWebResponse = DirectCast(request.GetResponse(), FtpWebResponse) 
    Dim responseStream As Stream = response.GetResponseStream() 
    Dim reader As New StreamReader(responseStream) 
    Dim ListDirectory As New List(Of String)() 
    Dim line As String = reader.ReadLine() 

    While Not String.IsNullOrEmpty(line) 
     ListDirectory.Add(line) 
     line = reader.ReadLine() 
    End While 

    reader.Close() 
    response.Close() 

    Using WebClient As New WebClient() 
     WebClient.Credentials = New System.Net.NetworkCredential(FTPUser, FTPPwd) 
     For i As Integer = 0 To ListDirectory.Count - 1 
      Dim LocalFilePath = LocalPath & ListDirectory(i).ToString() 
      If ListDirectory(i).Contains(".") AndAlso Not File.Exists(LocalFilePath) Then 
       Dim FTPPath As String = FTPUri & ListDirectory(i).ToString() 
       WebClient.DownloadFile(FTPPath, LocalFilePath) 
      End If 
     Next 
    End Using 
End Sub 
End Class