I am creating a console app that will delete pictures from a directory every 30 minutes. Problem is that its being populated by files every minute or so. So if I go and delete files in that directory then it may cause an error trying to delete a file thats being created just then or opened.
I currently have this code to copy the files to another directory and then delete them from the source directory.
Dim f() As String = Directory.GetFiles(sourceDir)
For i As Integer = 0 To UBound(f)
'Check file date here in IF statement FIRST...
File.Copy(f(i), destDir & f(i).Replace(sourceDir, ""))
If File.Exists(f(i)) = True Then
File.Delete(f(i))
End If
Debug.Print(f(i) & " to >>> " & destDir & f(i).Replace(sourceDir, ""))
Next
How can I use:
File.GetCreationTime(f(i))
in an IF statement checking IF the currently file its on is newer than 30 seconds ago?
OR
Is there a way of only populating:
Dim f() As String = Directory.GetFiles(sourceDir)
with only those files that are more than 30 seconds old?
There isn't a reliable way to detect if a file is locked or not. Even if you did find out (it is technically possible), it could be locked before you tried to delete it. There are other reasons a delete may fail. In your case, I don't think it matters what the reason was.
The only way is to put the call to delete in a try/catch and trap IOException, and then retry if you want.
You need to use a FileInfo object to get the CreatedTime and compare to Now. You can also use LastAccessTime or LastWriteTime, but since these are all new files being written then, you don't need to.
Private Sub DeleteFiles()
Dim files = From f In Directory.GetFiles("c:\temp")
Let fi = New FileInfo(f)
Where fi.Exists AndAlso fi.CreationTime <= DateTime.Now.AddSeconds(-30)
For Each f In files
Try
f.Delete()
Catch ex As Exception
If TypeOf ex Is IOException AndAlso IsFileLocked(ex) Then
' do something?
End If
'otherwise we just ignore it. we will pick it up on the next pass
End Try
Next
End Sub
Private Shared Function IsFileLocked(exception As Exception) As Boolean
Dim errorCode As Integer = Marshal.GetHRForException(exception) And ((1 << 16) - 1)
Return errorCode = 32 OrElse errorCode = 33
End Function
IsFileLocked function lifted from this other thread on SO
Dim NewFileDate As DateTime = DateTime.Now.AddSeconds(-30)
' get the list of all files in FileDir
Dim PicFiles As List(Of String) = System.IO.Directory.GetFiles("C:\", "*.txt").ToList()
' filter the list to only include files older than NewFileDate
Dim OutputList As List(Of String) = PicFiles.Where(Function(x) System.IO.File.GetCreationTime(x) < NewFileDate).ToList()
' delete files in the list
For Each PicFile As String In OutputList
'wrap this next line in a Try-Catch if you find there is file locking.
System.IO.File.Delete(PicFile)
Next
Obviously targeting .Net 3.5 or 4.0
Related
I am trying to figure out how to move 5 files
settings.txt
settings2.txt
settings3.txt
settings4.txt
settings5.txt
from one folder to another.
Although I know what the file names will be and what folder Name they will be in, I don't know where that folder will be on the Users computer.
My thought process is to use a FolderBrowseDialog which the user can browse to where the Folder is, and then when OK is pressed, it will perform the File copy to the destination folder, overwriting what's there.
This is what I have so far.
Dim FolderPath As String
Dim result As Windows.Forms.DialogResult = FolderBrowserImport.ShowDialog()
If result = DialogResult.OK Then
FolderPath = FolderBrowserImport.SelectedPath & "\"
My.Computer.FileSystem.CopyFile(
FolderPath & "settings.txt", "c:\test\settings.txt", overwrite:=True)
ElseIf result = DialogResult.Cancel Then
Exit Sub
End If
Rather than run this 5 times, is there a way where it can copy all 5 files at once
I know why IdleMind recommended the approach they did, but it would probably make for a bit more readable code to just list out the file names:
Imports System.IO
...
Dim result = FolderBrowserImport.ShowDialog()
If result <> DialogResult.OK Then Exit Sub
For Each s as String in {"settings.txt", "settings2.txt", "settings3.txt", "settings4.txt", "settings5.txt" }
File.Copy( _
Path.Combine(FolderBrowserImport.SelectedPath, s), _
Path.Combine("c:\test", s), _
True _
)
Next s
You can swap this fixed array out for a list that VB prepares for you:
For Each s as String in Directory.GetFiles(FolderBrowserImport.SelectedPath, "settings*.txt", SearchOption.TopDirectoryOnly)
File.Copy(s, Path.Combine("c:\test", Path.GetFilename(s)), True)
Next s
Tips:
It's usually cleaner to do a If bad Then Exit Sub than a If good Then (big load of indented code) End If - test all your known failure conditions at the start and exit the sub if anything fails, rather than arranging a huge amount of indented code
Use Path.Combine to combine path and filenames etc; it knows how to deal with stray \ characters
Use Imports to import namespaces rather than spelling everything out all the time (System.Windows.Forms.DialogResult - a winforms app will probably have all the necessaries imported already in the partial class so you can just say DialogResult. If you get a red wiggly line, point to the adjacent lightbulb and choose to import System.WIndows/Forms etc)
Once you have the selected folder, use a For loop to build up the names of the files you're looking for. Use System.IO.File.Exists() to see if they are there. Use System.IO.Path.Combine() to properly combine your folders with the filenames.
Here's a full example (without exception handling, which should be added):
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
If FolderBrowserImport.ShowDialog() = DialogResult.OK Then
Dim FolderPath As String = FolderBrowserImport.SelectedPath
For i As Integer = 1 To 5
Dim FileName As String = "settings" & If(i = 1, "", i) & ".txt"
Dim FullPathFileName As String = System.IO.Path.Combine(FolderPath, FileName)
If System.IO.File.Exists(FullPathFileName) Then
Dim DestinationFullPathFileName = System.IO.Path.Combine("c:\test", FileName)
My.Computer.FileSystem.CopyFile(FullPathFileName, DestinationFullPathFileName, True)
Else
' possibly do something in here if the file does not exist?
MessageBox.Show("File not found: " & FullPathFileName)
End If
Next
End If
End Sub
I'm fairly familiar with bash, but I'm very, ***very**** new to vb.net. I'm searching for an easy way to find files in a folder that end with .G1, .G2, .G3, etc. but NOT .GP1, .GP2, .GP3, etc. Then for each file I need to copy it to another folder using a different file name but the same extension. I've managed to figure this out for the unique files, but there will be an undefined number of these depending on the project and I need to make sure that I get them all. Hard coding is possible, but very, very ugly. Any suggestions?
Here's the remnants of a failed attempt:
Public Sub FindGFiles()
FileList = IO.Directory.GetFiles(searchDir, ".G[1-99]" + , IO.SearchOption.AllDirectories)
For Each foundfile As String In FileList
If foundfile.Contains(".G#") Then
'copy file somehow and retain file extension
Else
MsgBox("No match")
End If
Next
End Sub
The GetFiles-method does only support * and ? wildcard characters.
So you have to get all files with a *.G*-extension first.
In the For Each-loop one can then use the Like-operator to check the desired pattern:
Public Sub CopyGFiles(searchDir As String, destDir As String)
Dim fileList As String() = IO.Directory.GetFiles(searchDir, "*.G*", IO.SearchOption.AllDirectories)
Dim fileName As String
Dim extension As String
For Each foundfile As String In fileList
fileName = IO.Path.GetFileNameWithoutExtension(foundfile)
extension = IO.Path.GetExtension(foundfile)
If extension Like ".G#" OrElse
extension Like ".G##" Then
'copy file to destination, append "_new" to the filename and retain file extension
IO.File.Copy(foundfile, IO.Path.Combine(destDir, fileName & "_new" & extension))
Else
'pattern not matched
End If
Next
End Sub
The method-call would then be as follows:
CopyGFiles("C:\Temp", "C:\Temp\Dest")
This should be done inside a Try/Catch as different exceptions can occur when working with files.
Try
CopyGFiles("C:\Temp", "C:\Temp\Dest")
Catch ex As Exception
MessageBox.Show("An error occured" + vbCrLf + ex.Message)
End Try
i have been trying to figure out how to delete a .txt file that constantly change name exept the first 4 ex: THISTEXT-123-45.txt where THISTEXT stays the same but -123-45 changes.
I have found a way to detect it, but i don't know how to delete it.
Dim paths() As String = IO.Directory.GetFiles("C:\", "THISTEXT*.txt")
If paths.Length > 0 Then
Anyone knows the command line to delete that special .txt file?
I am using Visual Basic on visual studio 2013 framework 3.5.
Use the Delete method of System.IO.
Assuming you have write access to C:\
Dim FileDelete As String
FileDelete = "C:\testDelete.txt"
If System.IO.File.Exists( FileDelete ) = True Then
System.IO.File.Delete( FileDelete )
MsgBox("File Deleted")
End If
Deleting a file is quite simple - but dangerous! So be very careful when you're trying out this code.
Edit
To delete all file use *(asterisk) followed with the file extension
example C:\*.txt"
For multiple files
Dim FileDelete As String
FileDelete = "C:\"
For Each FileDelete As String In IO.Directory.GetFiles(FileDelete & "THISTEXT*.txt")
File.Delete(FileDelete)
Next
If you read the MSDN page on GetFiles, you will realize that you have the file name and path in your paths array. You can then iterate through the array deleting your matches.
Dim x as Integer
Dim paths() as String = IO.Directory.GetFiles("C:\", "THISTEXT*.txt")
If paths.Length > 0 Then
For x = 0 to paths.Length -1
IO.File.Delete(paths(x))
Next
End If
To build on the feedback you provided to Omar's answer, it appears that your file path and file name are separate.
You cannot provide them separated by a comma, as commas denote separate parameters passed to a subroutine or function.
To fix this, you need to concatenate them, for example:
Dim fileName As String = "foo.txt"
Dim filePath As String = "C:\"
Dim FileToDelete As String = fileName + filePath
To delete a single .*txt file if it exists:
If (deleteFile("C:\")) Then
MsgBox("File deletion successful")
Else
MsgBox("File couldn't be deleted with the following error: " + exception)
End If
alternatively with concatenation:
If (deleteFile("C:\") Then
MsgBox("File deletion successful")
Else
MsgBox("File couldn't be deleted with the following error: " + exception)
End If
Dim exception As String 'Place this at the beginning of your app's class.
Dim path As String = "C:\"
If (deleteFile(path)) Then
MsgBox("File deletion successful")
Else
MsgBox("File couldn't be deleted with the following error: " + exception)
End If
Private Function deleteFile(ByVal dir) As Boolean
Dim fileToRemove As String
Try
Dim paths() As String = IO.Directory.GetFiles(dir, "THISTEXT*.txt")
For i As Integer = 0 To paths.Length
fileToRemove = paths(i).ToString
System.IO.File.Delete(fileToRemove)
If (Not System.IO.File.Exists(fileToRemove)) Then
Return True
Else
exception = "Unknown error."
Return False
End If
Next
Return False
Catch ex As Exception
exception = ex.Message
Return False
End Try
Return False
End Function
The above function checks if the file exists, if it does it tries to delete it. If the file cannot be deleted, or an error occurs (which is handled), the Function returns False.
Simple example:
For Each path As String In IO.Directory.GetFiles("C:\", "THISTEXT*.txt")
Try
System.IO.File.Delete(path)
Catch ex As Exception
MessageBox.Show(path, "Unable to Delete File")
End Try
Next
I have a VB.NET program which lists some text files in a directory and loops through them. For each file, the program calls notepad.exe with the /p parameter and the filename to print the file, then copies the file to a history directory, sleeps for 5 seconds(to allow notepad to open and print), and finally deletes the original file.
What's happening is, instead of printing every single text file, it is only printing "random" files from the directory. Every single text file gets copied to the history directory and deleted from the original however, so I know that it is definitely listing all of the files and attempting to process each one. I've tried adding a call to Thread.Sleep for 5000 milliseconds, then changed it to 10000 milliseconds to be sure that the original file wasn't getting deleted before notepad grabbed it to print.
I'm more curious about what is actually happening than anything (a fix would be nice too!). I manually moved some of the files that did not print to the original directory, removing them from the history directory, and reran the program, where they DID print as they should, so I know it shouldn't be the files themselves, but something to do with the code.
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim f() As String = ListFiles("l:\", "997")
Dim i As Integer
Try
For i = 0 To f.Length - 1
If Not f(i) = "" Then
System.Diagnostics.Process.Start("Notepad.exe", " /p l:\" & f(i))
My.Computer.FileSystem.CopyFile("l:\" & f(i), "k:\" & f(i))
'Thread.Sleep(5000)
Thread.Sleep(10000)
My.Computer.FileSystem.DeleteFile("l:\" & f(i))
End If
Next
'Thread.Sleep(5000)
Thread.Sleep(10000)
Catch ex As Exception
End Try
End Sub
Public Function ListFiles(ByVal strFilePath As String, ByVal strFileFilter As String) As String()
'finds all files in the strFilePath variable and matches them to the strFileFilter variable
'adds to string array strFiles if filename matches filter
Dim i As Integer = 0
Dim strFileName As String
Dim strFiles(0) As String
Dim strExclude As String = ""
Dim pos As Integer = 0
Dim posinc As Integer = 0
strFileName = Dir(strFilePath)
Do While Len(strFileName) > 0
'check to see if filename matches filter
If InStr(strFileName, strFileFilter) Then
If InStr(strFileName, "997") Then
FileOpen(1, strFilePath & strFileName, OpenMode.Input)
Do Until EOF(1)
strExclude = InputString(1, LOF(1))
Loop
pos = InStr(UCase(strExclude), "MANIFEST")
posinc = posinc + pos
pos = InStr(UCase(strExclude), "INVOICE")
posinc = posinc + pos
FileClose(1)
Else : posinc = 1
End If
If posinc > 0 Then
'add file to array
ReDim Preserve strFiles(i)
strFiles(i) = strFileName
i += 1
Else
My.Computer.FileSystem.MoveFile("l:\" & strFileName, "k:\" & strFileName)
End If
'MsgBox(strFileName & " " & IO.File.GetLastWriteTime(strFileName).ToString)
pos = 0
posinc = 0
End If
'get the next file
strFileName = Dir()
Loop
Return strFiles
End Function
Brief overview of the code above. An automated program fills the "L:\" directory with text files, and this program needs to print out certain files with "997" in the filename (namely files with "997" in the filename and containing the text "INVOICE" or "MANIFEST"). The ListFiles function does exactly this, then back in the Form1_Load() sub it is supposed to print each file, copy it, and delete the original.
Something to note, this code is developed in Visual Studio 2013 on Windows 7. The machine that actually runs this program is still on Windows XP.
I can see a few issues. the first and most obvious is the error handling:
You have a Try.. Catch with no error handling. You may be running in to an error without knowing it!! Add some output here, so you know if that is the case.
The second issue is to do with the way you are handling Process classes.
Instead of just calling System.Diagnostics.Process.Start in a loop and sleeping you should use the inbuilt method of handling execution. You are also not disposing of anything, which makes me die a little inside.
Try something like
Using p As New System.Diagnostics.Process
p.Start("Notepad.exe", " /p l:\" & f(i))
p.WaitForExit()
End Using
With both of these changes in place you should not have any issues. If you do there should at least be errors for you to look at and provide here, if necessary.
I've got ASP.NET intranet application written in VB. It gets a file from the user, and then depending on a few different cases it may create a few copies of the file as well as move the original.
Unfortunately I've come across a case where I get this error:
Exception Details: System.IO.IOException: The process cannot access the file
'\\some\dir\D09_03_5_180_0.000-6.788.png' because it is being used by
another process.
Which is thrown by My.Computer.FileSystem.CopyFile. And that's fine that it's being used by another process - it may still be saving/downloading from the user or trying to copy while another thread(?) is copying, I don't really care about that, what I want to know:
Is there any way that I can tell VB to wait to copy (also move) the file until the file is no longer in use?
Thanks
Test if the file is in use and the do what you need to do.
Public Sub WriteLogFile(ByVal pText As String, ByVal psPath As String, ByVal psName As String)
Dim strFullFileName As String
Dim Writer As System.IO.StreamWriter
Dim Fs As System.IO.FileStream
Try
Dim DirectoryHandler As New System.IO.DirectoryInfo(psPath)
strFullFileName = psPath & "\" & psName & Date.Today.Month.ToString & "-" & Date.Today.Day.ToString & "-" & Date.Today.Year.ToString & ".txt"
If Not DirectoryHandler.Exists() Then
Try
Monitor.Enter(fsLocker)
DirectoryHandler.Create()
Finally
Monitor.Exit(fsLocker)
End Try
End If
Try
If CheckIfFileIsInUse(strFullFileName) = True Then
Thread.Sleep(500) ' wait for .5 second
WriteLogFile(pText, psPath, psName)
If Not Fs Is Nothing Then Fs.Close()
If Not Writer Is Nothing Then Writer.Close()
Exit Sub
End If
Monitor.Enter(fsLocker)
Fs = New System.IO.FileStream(strFullFileName, IO.FileMode.Append, IO.FileAccess.Write, IO.FileShare.Write)
Writer = New System.IO.StreamWriter(Fs)
Writer.WriteLine(Date.Now.ToString & vbTab & "ProcessID: " & Process.GetCurrentProcess.Id.ToString() & vbTab & pText)
Writer.Close()
Fs.Close()
Finally
Monitor.Exit(fsLocker)
End Try
Catch ex As Exception
Dim evtEMailLog As System.Diagnostics.EventLog = New System.Diagnostics.EventLog()
evtEMailLog.Source = Process.GetCurrentProcess.ProcessName.ToString()
evtEMailLog.WriteEntry(ex.Message, System.Diagnostics.EventLogEntryType.Error)
Finally
If Not Fs Is Nothing Then Fs.Close()
If Not Writer Is Nothing Then Writer.Close()
End Try
End Sub
Public Function CheckIfFileIsInUse(ByVal sFile As String) As Boolean
If System.IO.File.Exists(sFile) Then
Try
Dim F As Short = FreeFile()
FileOpen(F, sFile, OpenMode.Append, OpenAccess.Write, OpenShare.Shared)
FileClose(F)
Catch
Return True
End Try
End If
End Function
Hmm... not directly.
What most implementations are doing, is making a retry of copying the file, with a small timeframe (some seconds)
if you want to make a nice UI, you check via Ajax, if the copying process went well.
Well, it turns out that waiting would not work in this case:
When trying to copy a file you cannot copy a file from one location to the same location or it will throw an error (apparently). Rather than just pretending to copy the file, VB actually tries to copy the file and fails because the copy operation is trying to copy to the file it's copying from (with overwrite:=True at least).
Whoops!