I am having trouble using FileSystemWatcher [vb.net]

问题

This is my first time using FileSystemWatcher, but it's not working. It doesn't trigger when a file is created in the monitored paths. My goal is to monitor changes in the Program File directories. I will compare files copied against an online list (which I download). I'm not finished with that part yet [what it will do if it finds a match]. What am I doing wrong?

I've also noticed some say that FSW is glitchy or has issues. If you think I should use something else, let me know.

Imports System.IO
Imports System.Net
Public Class Form1
Private WithEvents pFiles As FileSystemWatcher
Private WithEvents pFiles32 As FileSystemWatcher
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    Me.WindowState = FormWindowState.Minimized
    Me.ShowInTaskbar = False

    pFiles = New FileSystemWatcher("C:\Program Files", "*.*")
    pFiles.IncludeSubdirectories = True
    If Environment.Is64BitOperatingSystem.Equals(True) Then
        pFiles32 = New FileSystemWatcher("C:\Program Files (x86)", "*.*")
        pFiles32.IncludeSubdirectories = True
    End If
End Sub

Sub badFiles(ByVal sender As Object, ByVal e As System.IO.FileSystemEventArgs) Handles pFiles.Created
    MsgBox("Triggered in x64 folder!")
    Dim fileInfo = New FileInfo(e.FullPath)
    Dim createWord = fileInfo.Name.ToString()
    Dim myWebClient As New System.Net.WebClient
    myWebClient.DownloadFile("http://www.systemlookup.com/lists.php?list=1&type=filename&search=" & createWord & "&s=", "C:\Users\Tyler\Desktop\" & createWord & ".html")
    Dim reader = IO.File.ReadAllText("C:\Users\Tyler\Desktop\" & createWord & ".html")
    If reader.Contains("No results. Please try a different search term.") Then
        MsgBox("Not Found!")
    Else
        If reader.Contains(createWord) Then
            MsgBox("Found!")
        Else
            MsgBox("Not Found!")
        End If
    End If
End Sub

Sub badFiles32(ByVal sender As Object, ByVal e As System.IO.FileSystemEventArgs) Handles pFiles32.Created
    MsgBox("Triggered in x86 folder!")
    Dim fileInfo = New FileInfo(e.FullPath)
    Dim createWord = fileInfo.Name.ToString()
    Dim myWebClient As New System.Net.WebClient
    myWebClient.DownloadFile("http://www.systemlookup.com/lists.php?list=1&type=filename&search=" & createWord & "&s=", "C:\Users\Tyler\Desktop\" & createWord & ".html")
    Dim reader = IO.File.ReadAllText("C:\Users\Tyler\Desktop\" & createWord & ".html")
    If reader.Contains("No results. Please try a different search term.") Then
        MsgBox("Not Found!")
    Else
        If reader.Contains(createWord) Then
            MsgBox("Found!")
        Else
            MsgBox("Not Found!")
        End If
    End If
End Sub
End Class

回答1:

It appears you are replacing your module level variables:

Private WithEvents pFiles As FileSystemWatcher
Private WithEvents pFiles32 As FileSystemWatcher

Private Sub Form1_Load(ByVal sender As System.Object, 
      ByVal e As System.EventArgs) Handles MyBase.Load

    ' this creates a NEW pfiles which only exists in FormLoad
    Dim pFiles As FileSystemWatcher = New FileSystemWatcher("C:\Program Files", 
           "*.*")
    pFiles.IncludeSubdirectories = True

Even you were to manually hook it up using AddHandler, that pFiles goes out of scope at the end of Form Load. The correct syntax would be:

' since it is already declared (DIM) you just need to instance it (NEW):
pFiles = New FileSystemWatcher(...

来源：https://stackoverflow.com/questions/24578937/i-am-having-trouble-using-filesystemwatcher-vb-net

标签

vb.net

filesystemwatcher