VB.Net FileSystemWatcher - Multiple Folders and Multiple Files - vb.net

Question

I have a requirement of monitoring a root folder under which there are multiple folders and each folder containing multiple files (.csv) These files are being copied to a workstation from a server using some other third party tool. I have to monitor the workstation root's folder and as an when a .csv file is created or updated in any of the child folders, I have to write the .csv file data (updated or new) to a sql server database. While writing the data to the sql server, I need to capture the child folder name in which the .csv file was updated/created. This way I can have separate folder's data in one database file.
While running the program on the workstation pc, the application crashes without any specific error message. And since the app is run on a remote pc, I cannot debug the app to check which line is causing the crash. Below is the code:
Public Class FolderWatchAndProcess
Dim blnMonitorUpdated As Boolean = True
Dim blnMonitorCreated As Boolean = True
Dim blnShowMessage As Boolean
Dim strFullFileName As String
Dim strFileName As String
Dim strFolderName As String
Private Delegate Sub updateLabel(ByVal newLabel As String)
Private Sub updateLabelHandler(ByVal labelText As String)
lblMetNo.Text = labelText
End Sub
Private Sub ReadAndInsertCSVData()
' This routine checks for duplicates and inserts new records into the sql server database
End Sub
Private Sub Form_Load(sender As Object, e As EventArgs) Handles MyBase.Load
'lblMonitorPath.Text = "C:\RootFolder\"
'btnStartWatching_Click(Nothing, Nothing)
'Me.WindowState = FormWindowState.Minimized
End Sub
Private Sub btnStartWatching_Click(sender As Object, e As EventArgs) Handles btnStartWatching.Click
btnStartWatching.Text = "Stop Watching"
Dim aFileWatcherInstance As ArrayList = New ArrayList
For Each sMonitorFolder As String In lstFolders.Items
If IO.Directory.Exists(sMonitorFolder) Then
Dim oFileWatcher As FileSystemWatcher = New FileSystemWatcher
oFileWatcher.Path = sMonitorFolder
oFileWatcher.Filter = "*.CSV"
If blnMonitorUpdated Then
AddHandler oFileWatcher.Changed, AddressOf Me.FileSystemWatcherUpdated
Else
'RemoveHandler , AddressOf Me.FileSystemWatcherUpdated
End If
If blnMonitorCreated Then
AddHandler oFileWatcher.Created, AddressOf Me.FileSystemWatcherCreated
Else
'RemoveHandler , AddressOf Me.FileSystemWatcherCreated
End If
oFileWatcher.EnableRaisingEvents = True
aFileWatcherInstance.Add(oFileWatcher)
End If
Next
End Sub
Private Sub FileSystemWatcherCreated(ByVal sender As Object, ByVal e As System.IO.FileSystemEventArgs)
strFullFileName = e.FullPath
strFileName = Mid(e.Name, 3, Len(e.Name))
strFolderName = strFileName.Split("_")(0)
If Me.InvokeRequired Then
Dim d As New updateLabel(AddressOf updateLabelHandler)
Me.BeginInvoke(d, New Object() {strFolderName})
Else
updateLabelHandler(strFolderName)
End If
ReadAndInsertCSVData()
End Sub
Private Sub FileSystemWatcherDeleted(ByVal sender As Object, ByVal e As System.IO.FileSystemEventArgs)
'A file has been deleted from the child directory.
End Sub
Private Sub FileSystemWatcherUpdated(ByVal sender As Object, ByVal e As System.IO.FileSystemEventArgs)
strFullFileName = e.FullPath
strFileName = Mid(e.Name, 3, Len(e.Name))
strFolderName = strFileName.Split("_")(0)
If Me.InvokeRequired Then
Dim d As New updateLabel(AddressOf updateLabelHandler)
Me.BeginInvoke(d, New Object() {strFolderName})
Else
updateLabelHandler(strFolderName)
End If
ReadAndInsertCSVData()
End Sub
End Class
Any help would be appreciated.

Answer 1

the Changed event will fire multiple times:
https://msdn.microsoft.com/en-us/library/system.io.filesystemwatcher.changed(v=vs.110).aspx
probably you can use the IsFileLocked function that mention at here:
I keep getting exception sometimes on System.Threading.Tasks.TaskCompletionSource<bool> how can i solve it?