To start with it has been many years since I have done much programming, probably about 15 years, in fact VB 6 was still being taught then so I'm not up to date on anything and can get lost in what I'm reading but I am trying. I'm using Visual Studio 2019 and trying to create a VB Windows Forms App that uses the FileSystemWatcher. Unfortunately the only solutions to my problem that I could find are in C#. I tried to transfer them to my app but couldn't get them to work. Actually Visual Studio wasn't happy with what I put in and wouldn't run at all, probably due to incorrect syntax.
This part of my little app is supposed to copy a file that another program creates, while the other program is running, and place the copy in another folder. It seemed simple, detect that the file had been changed and then copy the changed file. Well I came across a few problems.
The first problem is that if I create an empty file the code works most times with no problems but occassionally 2 copies of the file are created. I could live with that but.
If I replace the empty file with a larger file, the file that it is meant to copy, then it can make 3 or 4 copies and most times produces a messagebox telling me that it can't access the file because it is in use. The main program is also minimised to display the error message, which I don't want.
Even if my app is the only program running and I replace the watched file manually with the larger file I still get the file in use error, so I am assuming that the event has been triggered twice and one of them is the process that is using the file and causing the error.
If I tell the error message to cancel then my program continues and produces only 1 copy of the file. Which is what I do want.
The second problem is that the file being copied is also accessed by another program for a short period imediately after it has been changed and this also causes an extra few copies of it to be made and sometimes a file in use error message box appears, and again the main program is minimised to display the error message. I originally had other IO.NotifyFilters in place that weren't really necassary and thought that they may have been triggering the errors so I removed them, but it made no difference.
The most common error is that the file is in use but there has also been the odd "Unhandled exception has occured in your application. could not find file.". The only reason that I can think of for this error is that the file may have been renamed to a backup file and a new version created by the main program at the exact time my program tried to access it.
From what I have read the FileSystemWatcher can trigger multiple times and I presume that this is what is causing the duplicate copies from both problems.
I need my app to make only 1 copy without the error messagebox appearing as this program needs to run in the background with no user input. Essentially this part of my app is an external program to backup a file when the file changes because the main program changes this file often but only seems to back up the file every few hours.
The following code is what I have used but nothing that I have tried has caught the error so I removed the error event handler. This code was copied from something else that was similar and in C# then modified for my purpose. I thought that the {} were used for C# not VB but it seems to work and if I take them out it won't.
My code for the FileSystemwatcher is:-
WatchFile = New System.IO.FileSystemWatcher With {
.Path = Path.GetDirectoryName(strArkMapFileNamePath),
.Filter = Path.GetFileName(strArkMapFileNamePath),
.NotifyFilter = IO.NotifyFilters.LastWrite
}
' add the handler to each event
AddHandler WatchFile.Changed, New FileSystemEventHandler(AddressOf OnLastWrite)
'Set this property to true to start watching
WatchFile.EnableRaisingEvents = True
The event handler is:-
Private Sub OnLastWrite(sender As Object, e As FileSystemEventArgs)
'Copy the Save file to a new folder and rename it.
My.Computer.FileSystem.CopyFile(
strArkMapFileNamePath,
strBackupPath & "\" & strArkMapFileName & "_" &
DateTime.Now.ToString("dd.MM.yyyy_hh.mm.ss") & ".ark",
Microsoft.VisualBasic.FileIO.UIOption.OnlyErrorDialogs,
Microsoft.VisualBasic.FileIO.UICancelOption.DoNothing)
End Sub
I added an error event handler after AddHandler WatchFile.Changed, New FileSystemEventHandler(AddressOf OnLastWrite) but that did nothing.
I tried to add an on error statement before the end sub and that did nothing either, I presume because the Microsoft.VisualBasic.FileIO.UIOption.OnlyErrorDialogs, caught the error first.
I got frustrated and tried to add a statement before the Microsoft.VisualBasic.FileIO.UIOption.OnlyErrorDialogs, but it didn't like that and I didn't expect it to work.
So how do I catch the errors before the FileSystemWatcher acts on the error?
I don't know what I am doing wrong so any help would be appreciated.
Also if anybody could offer code for what I need to do can it please be code for a Windows Forms App because I don't seem to have much luck in converting C# or anything else.
Edit
I have replaced the My.Computer.FileSystem.CopyFile with the File.Copy method as suggested and added a few extra bits..
Private Sub OnLastWrite(sender As Object, e As FileSystemEventArgs)
'Verify that source file exists
If File.Exists(strArkMapFileNamePath) Then
'Copy the Save file to a new folder and rename it.
Dim i As Integer
For i = 0 To 3
Try
' Overwrite the destination file if it already exists.
File.Copy(strArkMapFileNamePath, strBackupPath & "\" & strArkMapFileName & "_" & DateTime.Now.ToString("dd.MM.yyyy_hh.mm.ss") & ".ark", True)
i = 3
' Catch exception if the file was already copied.
Catch copyError As IOException
'If copy failed reset counter
i += 1
End Try
Next
End If
End Sub
Although this shouldn't be required because this is done before the FileSystemWatcher is enabled I have added an If statement to check that the files exists before attempting to copy the file.
I'm not entirely happy with the loop but I know under normal conditions that it's not going to be an endless loop.
Is there a way to just catch the specific errors that I would need to deal with or will it be fine the way it is?
I will probably still need to work out how to stop the FileSystemWatcher from sending more than 1 event or somehow make multiple events appear as 1.
The If statement was the last thing that I added and for some reason the program now seems to only make 1 copy and appears to be faster.
The other external program that accesses the file being copied must be slower to react than my program because now it displays a message that it's waiting until my program has finished copying the file.
My program is now performing as it was intended but I believe that it is just a matter of timing rather than the correct code.
Related
I made a few improvements to code that has been functioning without issues. On the development, the app runs with a problem. Installed on a test computer and it does not run unless I right click and run as administrator. The below code is where gets not running as Administrator.
The for loop is adding file names to a list. Administrator the program just ends no errors just quits. i counter gets to 3 of a total of 6 files. Never gets through to post the message "Did it make it here". But does post the message inside the for loop. i counts to 3. If run as admin then no issues. All file names are short and basic with no special characters. The files locations is Application.CommonAppDataPath. The loop is called from Form load.
Hoping someone could tell me what is going on.
Try
Selected_Machine = XMLReadSetting("Machine", "Selected", "Selexx")
For i = 0 To UBound(files)
MessageBox.Show("Here 2 i " & i & " File Name" & files(i))
cboMachine.Items.Add(IO.Path.GetFileNameWithoutExtension(files(i)))
If Selected_Machine = IO.Path.GetFileNameWithoutExtension(files(i)) Then
cboMachine.SelectedItem = IO.Path.GetFileNameWithoutExtension(files(i))
End If
Next
Catch err As SyntaxErrorException
MessageBox.Show(err.Message)
End Try
MessageBox.Show("Did it make it here?")
Found the issue. Inside the for loop it make a change that calls the text changed event of the list box. In the text changed event I write data to a settings file. The settings file did not have write access. Not sure how that happend but problem solved
Thank you all for the help.
I'm getting an IOException (file in use by another process) error when trying to delete an .xlsx file. I moved the delete code to the front of Form_Load() just to make absolutely certain that nothing else I was doing was trying to open or read it.
Process Explorer can't find any references to the file to see what else might be trying to use it.
The file properties indicate that the user and system have full control.
I don't know what to look at next.
Private Sub PreEdit2_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
My.Computer.FileSystem.DeleteFile("\\HOSTNAME\Folder\Import Data\Other Import Files\" & "9710.xlsx")
I tried a local reference to the file just for good measure.
My.Computer.FileSystem.DeleteFile("C:\Folder\Import Data\Other Import Files\" & "9710.xlsx")
Really stumped here. Any suggestions sincerely appreciated.
EDIT:
Modified my program to delete all kinds of other files in the same directory. They delete with no problem.
Created an empty test program with one line that tries to delete the file
and it gets the same IOException.
So, my program isn't doing it. The error says something else is using the file, no monitoring program I have used shows the any process involved with the file, and File Explorer can delete it? Strange things are afoot at the Circle K.
EDIT 2:
I have moved the file and tried deleting it in lots of different directories. I can delete it everywhere else I try it. The only place I don't seem to be able to delete it (with my new single purpose test program) is in the directory it was originally copied to. It should be remembered that all of the other files in that directory I can use the program to delete with no problem.
So I have tons of data in my workbook that I need to pass on to my users in a way that allows them to interact with the workbook..., but also limits what they can actually do. So I have made it so they can access certain pages to Add needed data, then I've given access to a menu page so they can run a report.
This report I have found is best if it's an html page.
To that end, I have tried several different ways, save as...and publish. I like the publish version, but I can not for the life of me get this working. All the samples I see, appear to be the same. Here is the line of code in question:
ActiveWorkbook.PublishObjects.Add(xlSourceSheet, ActiveWorkbook.Path & ".htm, "Sheet1", "", xlHtmlStatic, "", "Report Title").Publish True
Every time I get a run time error '1004':
Method 'Publish' of object 'PublishObject' failed
I have the above line of code in a sub, am I missing something? Do I need to set up the publish differently? Thanks for any ideas.
I have had a similar mysterious problem that sometimes it (.Publish) works and sometimes it doesn't, when I try publish.
However, I think the problem might be, in cases when it doesn't work right off the bat, to first save the relevant region as a webpage so that it exists already on the server. After that region has been saved at least once (manually or else maybe with .SaveAs .. see below), then the publish might work.
Here is an example of how I get this to work more consistently, something to convey the structure that works for me:
wkb=ActiveWorkbook.Name 'save wb for later access
url="http://a.com/b.htm" 'save to Internet
sheetname="c"
Sheets(sheetname).Range("d1:e2").Select 'activating sheet may be necessary
On Error Resume Next 'anticipate error to handle it
'Now comes the publish line the first time... which may work.. or not
ActiveWorkbook.PublishObjects.Add(xlSourceRange,url,sheetname,"d1:e2",xlHtmlStatic,"blah","moreblah").Publish (True) 'may fail to create page on website if page didn't already exist
theerr=Err.Number
On Error GoTo 0 'back to default error handling (none)
If theerr <> 0 Then 'if here perhaps because page nonexistent
'msgbox "maybe add warning here [FYI]"
Sheets("dummysheetwithlittleornodata").Copy 'will create workbook
On Error Resume Next
ActiveWorkbook.SaveAs url 'may fail to create webpage first time
ActiveWorkbook.saveAs url 'twice needed for some reason sometimes. [works for me]
On Error GoTo 0
'with fresh dummy html page created, now publish should hopefully work.. let's try again
ActiveWorkbook.Close savechanges:=False 'clean up and avoid popup
Workbooks(wkb).Activate 'get back to correct wkb
Sheets(sheetname).Range("d1:e2").Select
ActiveWorkbook.PublishObjects.Add(xlSourceRange,url,sheetname,"d1:e2",xlHtmlStatic,"blah","moreblah").Publish (True) 'hopefully if failed first time, now it succeeded ! good luck.
End If
The above code structure has allowed me to solve several publish problems I was having. All the techniques together have been enough so far to allow me to save a range from a sheet as a webpage (to server I have write access to) without having to do anything manually (like a manual save or even click on popup). Good Luck.
[The different non-obvious techniques include activating a range before trying a range publish, using the error handling approach and anticipating failure at certain points, the 2x saveas to compensate for mysterious inconsistent failures when using one saveas only, closing and getting back to original workbook cleanly, and using saveas to "guarantee" page exists in form that will make publish to succeed more consistently.]
I'm creating a html page that will import an excel file in to a tracking system. On a button click event excel file is located / ssis package is fired / data imported then closed out. Thats the idea work flow. Problem is the excel file access is being denied before the package even executes
Here is the exact error :
I've tried :
excel file properties have been shared to everyone
identity impersonate set to true
hard coding the path
here is the VB code
Protected Sub bntExecute_Click(sender As Object, e As EventArgs) Handles btnExecute.Click
Dim app As Application = New Application()
Dim package As Package = Nothing
'Dim fileName As String = "C:\Users\Desktop\T. Bryant III\PTSID_Update_Template"'
Try
Dim fileName As String = Server.MapPath(System.IO.Path.GetFileName(FileUpload1.PostedFile.FileName.ToString()))
FileUpload1.PostedFile.SaveAs(fileName)
package = app.LoadPackage("#C:\Users\Desktop\T.Bryant III\KitImport", Nothing)
'excel connection from package'
package.Connections("SourceConnectionExcel").ConnectionString = "provider=Microsoft.Jet.OLEDB.4.0data source =" + fileName + "Extended Properties = Excel 8.0"
'Execute the pakage'
Dim results As Microsoft.SqlServer.Dts.Runtime.DTSExecResult = package.Execute()
Catch ex As Exception
Throw ex
Finally
package.Dispose()
package = Nothing
End Try
End Sub
Thanks in advance or if there is an easier way to do this please let me know. The package when executing it in ssis works fine with its own connection manager etc.
A few things to try. If they don't work for you as permanent solutions, they should at least confirm that your code is working and you are dealing with a persmissions issue (which appears to be the case).
Move your file to the public folder (C:\Users\Public).
Run your application (or web browser) as an administrator (if applicable to your version of Windows).
If you are using a web browser, try using a different one.
If nothing else works, try pasting your code into a Windows Form Application.
If you still get the same error after trying all of this, it's time to take another look at your code. Remove the Try/Catch block to determine precisely which line is throwing the error. If you've tried hard coding, I'm guessing it's the SaveAs method. I'm not sure what class FileUpload1 is, but some SaveAs methods won't overwrite existing files unless you explicitly tell them to. Check the appropriate documentation and see if you don't need to pass a True value somewhere along with filename.
Update us with the results. At the very least, this should narrow down your problem and allow for a better diagnosis of it.
I have a program that takes a template .docx file and populates it with data, saving a copy afterwards. The program itself works fine and I got a nice try..catch in main sub in case something fails, so the file is closed regardless.
The problem is that if it crashes completely, i.e. is forced to close (or manually force closed if it hangs), it will keep the process running with the opened template, so next time it;s launched, you'll get the read only error when trying to open it.
So the question: Is there a way to clean up afterwards, without having to end process via task manager? Or maybe a way of opening it without locking it out? Making a temp copy maybe?
Fixed with this:
Sub KillUnusedWordProcess()
Dim oXlProcess As Process() = Process.GetProcessesByName("Winword")
For Each oXLP As Process In oXlProcess
If Len(oXLP.MainWindowTitle) = 0 Then
oXLP.Kill()
End If
Next
End Sub