Poll a directory looking for files with a certain extension - vb.net

Question

I'm writing a script to look in a directory, read the file name and use a part of the file name to run a SQL query to amend a DB, then copy the files to a new location and delete the original.
Once this is done it sends an email confirmation to a predefined email address.
I have the majority in place but am not able to Poll a Dir and process all files that may be there. Im new to this VB.net stuff and to get the other stuff working iv just named it at the beginning.
Any help would be greatly appreciated.
Dim fileName As String = "C:\temp\Input\VBTEST1.success"
Dim pathname As String = "C:\temp\Input\"
Dim result As String
Dim sourceDir As String = "C:\temp\Input\"
Dim processedDir As String = "C:\temp\Input\Processed\"
Dim fList As String() = Directory.GetFiles(sourceDir, "*.success")
Dim sqlCommand As SqlCommand
Public Sub Main()
result = Path.GetFileName(fileName)
Console.WriteLine("GetFileName('{0}') returns '{1}'", fileName, result)
Dim betacell As String = result
betacell = (result.Remove(7, 8))
Dim connection As New SqlConnection(My.Settings.connectionString)
connection.Open()
Dim updateTransaction As SqlTransaction = connection.BeginTransaction()
Dim sqlQ As String = "UPDATE " & My.Settings.JobTb & " SET Status = '10' WHERE JobNumber ='" & betacell & "'"
sqlCommand = New SqlCommand(sqlQ, connection, updateTransaction)
sqlCommand.ExecuteNonQuery()
updateTransaction.Commit()
connection.Close()
SendEmail(My.Settings.emailUsers, "EMAIL TEXT")
Call MoveFiles()
End Sub
I'm all chuffed now as iv also managed to make it look for all files with a .success extension. Now it processes all files and not the one named in the code.
Module Module1
Dim sourceDir As String = My.Settings.watchPath
Dim processedDir As String = My.Settings.processedPath
Private loggerName As String = "EmailReleases"
Public Sub log(ex As Exception)
Console.WriteLine("Error: " & ex.ToString)
End Sub
Public Sub log(ByVal s As String)
Console.WriteLine(DateTime.Now.ToString & " [" & loggerName & "] " & s)
End Sub
Public Sub Main()
Dim inputFiles As String() = Directory.GetFiles(sourceDir, "*.success")
log("Starting processing of .success files in '" & sourceDir & "' ... ")
If (inputFiles.Length > 0) Then
Dim connection As New SqlConnection(My.Settings.connectionString)
connection.Open()
For Each fileName As String In inputFiles
Dim sqlCommand As SqlCommand
Dim fFile As New FileInfo(fileName)
log(" Processing " & fFile.Name)
Dim betacell As String = fFile.Name.Substring(0, fFile.Name.Length - 8)
'Update Status on Database with the use of the Betacell
Dim updateTransaction As SqlTransaction = connection.BeginTransaction()
Dim sqlQ As String = "UPDATE " & My.Settings.JobTb & " SET Status = '10' WHERE JobNumber ='" & betacell & "'"
sqlCommand = New SqlCommand(sqlQ, connection, updateTransaction)
Dim result = sqlCommand.ExecuteNonQuery()
'Email COnfirmation
SendEmail(My.Settings.emailUsers, "EMAIL TEXT")
If (result > 0) Then
'Move the file
fFile.MoveTo(processedDir & fFile.Name)
updateTransaction.Commit() ' make sure to commit only in case moving the file is OK
Else
log("ERROR - Betacell '" & betacell & "' not found in database!")
updateTransaction.Rollback()
End If

Answer 1

Rather than polling a folder (i.e. checking every n seconds whether it has new files) it's much more efficient to have the operating system notify you of changes in that folder. You can do this by creating a FileSystemWatcher. There is an example on MSDN.
However, if you did want to poll a folder, it's actually nice and easy - just wrap the following code in a Timer. Please note I normally code in C#, so apologies if the syntax is not 100%...
Imports System.IO
....
For Each file as String in Directory.GetFiles("C:\SomeFolder")
DoSomethingWithFile (file)
Next