I have an application that generates documents.
However if a document is already open, then the generated new document cannot override the opened document, so no changes occur.
How can I properly check whether the document is already open or not? (And if open, then close it)
This code is working for me
Public Function FileInUse(ByVal sFile As String) As Boolean
Dim thisFileInUse As Boolean = False
If System.IO.File.Exists(sFile) Then
Try
Using f As New IO.FileStream(sFile, FileMode.Open, FileAccess.ReadWrite, FileShare.None)
' thisFileInUse = False
End Using
Catch
thisFileInUse = True
End Try
End If
Return thisFileInUse
End Function
You may try like this:
If File.Exists(Application.StartupPath & "\~$MyWordDocument.doc") Then
MsgBox("File is open")
Exit Sub
End If
Also check FAQ: How do I check whether a file is in use?
Related
I get the feeling this is something really simple, but I've tried I don't know how many permutations of vbNewLine, Environment.NewLine, sMessage & vbNewLine (or Environment.Newline) I've tried, or how many pages on this site, or through Google I've looked at but nothing has worked.
I even tried getting help from a VB.Net discord channel I'm a part of and they suggested to do the same things that I've done and the procedure is still writing each new log entry at the end of the previous one in a continuous string. My writer is below. Am I missing something simple?
Edit: The code that worked is below in case anyone else comes along with the same issue. If you want to see the original code it's in the edit log.
Option Explicit On
Imports System.IO
Public Class WriteroLog
Public Shared Sub LogPrint(sMessage As String)
Dim AppPath As String = My.Application.Info.DirectoryPath
If File.Exists($"{AppPath}\Log.txt") = True Then
Try
Using objWriter As StreamWriter = File.AppendText($"{AppPath}\Log.Txt")
objWriter.WriteLine($"{Format(Now, "dd-MMM-yyyy HH:mm:ss")} – {sMessage}")
objWriter.Close()
End Using
Catch ex As Exception
MsgBox(ex)
Return
End Try
Else
Try
Using objWriter As StreamWriter = File.CreateText($"{AppPath}\Log.Txt")
objWriter.WriteLine($"{Format(Now, "dd-MMM-yyyy HH:mm:ss")} – {sMessage}")
objWriter.Close()
End Using
Catch ex As Exception
MsgBox(ex)
Return
End Try
End If
End Sub
End Class
The File.AppendText() method creates a new StreamWriter that is then used to append Text to the specified File.
Note, reading the Docs about this method, that you don't need to verify whether the File already exists: if it doesn't, the File is automatically created.
As a side note, when creating a Path, it's a good thing to use the Path.Combine method: it can prevent errors in the path definition and handles platform-specific formats.
Your code could be simplified as follows:
Public Shared Sub LogPrint(sMessage As String)
Dim filePath As String = Path.Combine(Application.StartupPath, "Log.Txt")
Try
Using writer As StreamWriter = File.AppendText(filePath)
writer.WriteLine($"{Date.Now.ToString("dd-MMM-yyyy HH:mm:ss")} – {sMessage}")
End Using
Catch ex As IOException
MsgBox(ex)
End Try
End Sub
The File.CreateText does not assign result to "objWrite", should be:
objWriter = File.CreateText($"{AppPath}\Log.Txt")
Not really sure if this is the root of your problem, but it is an issue.
In essences, your logic is re-opening or creating the stream "objWriter" for every call to this method. I would recommend you initialize "objWriter" to Nothing and only define if it is Nothing.
Set to Nothing as below.
Shared objWriter As IO.StreamWriter = Nothing
Then add check for Nothing in logic.
I've constructed a VB.Net application which loads data into an Excel spreadsheet. The application works fine, but I've added a functionality to test whether the workbook is Open, and if so, the application terminates. Otherwise, if the workbook Is Not Open, then the user can proceed to fill information in the application. My issue is that when is when the worksheet is not open, my code blows up due to the workbook being "somehow opened." I need to close any processes, then proceed. Here's my code for checking if the workbook is open or not:
1st, my module, which sets up the a Boolean check:
Public Module ExcelCheck
Public Function Test(ByRef sName As String) As Boolean
Dim fs As FileStream
Try
fs = File.Open(sName, FileMode.Open, FileAccess.Read, FileShare.None)
Test = False
Catch ex As Exception
Test = True
End Try
End Function
End Module
Then my handler for a button on the form that does the check:
Private Sub btnOpenFileCheck_Click(sender As Object, e As EventArgs) Handles btnOpenFileCheck.Click
'Evaluate if the workbook is being used:
Dim bExist As Boolean
bExist = Test("\\netshareA\c$\Users\Pete\Desktop\TestUnits\Machines.xls")
If bExist = True Then
MessageBox.Show("The file is open... Please try again later.", "EXCEL FILE IN USE: Abort", MessageBoxButtons.OK)
Me.Close()
Else bExist = False
MessageBox.Show("The file is NOT open... You may proceed...", "EXCEL FILE NOT OPEN", MessageBoxButtons.OK)
Dim xlOpenItem As New Excel.Application
Dim xlOpenWB As Excel.Workbook = xlOpenItem.Workbooks.Open("\\netshareA\c$\Users\Pete\Desktop\TestUnits\Machines")
xlOpenWB.Close(SaveChanges:=False, Filename:="\\netshareA\c$\Users\Pete\Desktop\TestUnits\Machines.xls", RouteWorkbook:=False)
txtCPUSerial.Focus()
End If
End Sub
What happens when the book isn't open is the proper dialog to continue runs via the illustration:
But then an Excel dialog appears saying the following:
'\\netshareA\c$\Users\Pete\Desktop\TestUnits\Machines.xls'
is currently in use. Try again later.
Then, it finally blows up and I have the line of referenced:
Dim xlOpenWB As Excel.Workbook = xlOpenItem.Workbooks.Open("\\netshareA\c$\Users\Pete\Desktop\TestUnits\Machines")
My logic is that I need to have an open instance of an Excel object, then close that instance in order to terminate any inadvertent running process. I actually open the workbook in another submit handler, with the Excel objects and variables set well, but that's not my issue. How can I smoothly make sure the workbook object is closed here as as to not throw an exception that it isn't?
After much tinkering around, I've found out exactly what my problem was - I didn't close out the opened file stream:
Public Module ExcelCheck
Public Function Test(ByRef sName As String) As Boolean
Dim fs As FileStream
Try
fs = File.Open(sName, FileMode.Open, FileAccess.Read, FileShare.None)
Test = False
fs.Close() 'This closes out the initially opened file stream for checking.
Catch ex As Exception
Test = True
End Try
End Function
End Module
I eventually came back to the module and wondered what happens if I just close out and use fs.Close() and it did the trick. No more blow ups! Hope this helps someone else whom might struggle with a similar file stream issue.
I am implementing a Save File button in my VB.NET Windows Forms application.
I am attempting to encapsulate the normally expected behaviour of Save buttons in Windows applications. I.E: If a file was already selected then open the current file it, write to it and save it; else if there is no current file, or Save As was used, then show a SaveFileDialog, then open, write and save just the same.
I currently have coded the function below but I keep getting an exception:
Cannot access a closed file
The file is created just fine, but is empty (It should contain "Test string"). I can't understand how the file is closed unless some kind of garbage collection is doing away with it somehow??
The current code:
Function SaveFile(ByVal Type As ProfileType, ByVal suggestedFileName As String, ByVal saveAs As Boolean, ByVal writeData As String) As Boolean
Dim FileStream As Stream = Nothing
Dim FolderPath As String = Nothing
Dim CancelSave As Boolean = False
Dim SaveFileDialog As SaveFileDialog = New SaveFileDialog()
Try
If Type = ProfileType.Product Then 'Select the initial directory path
FolderPath = ProductPath
Else
FolderPath = ProfilePath
End If
If (FileName = String.Empty Or saveAs = True) Then 'If a file is not already selected launch a dialog to allow the user to select one
With SaveFileDialog
.Title = "Save"
.AddExtension = True
.CheckPathExists = True
.CreatePrompt = False
.DefaultExt = "xml"
.Filter = "Xml Files (*.xml)|*.xml"
.FilterIndex = 0
.FileName = suggestedFileName
.InitialDirectory = FolderPath
If .ShowDialog(Me) = Windows.Forms.DialogResult.OK Then
FullyQualfiedPathName = New String(SaveFileDialog.FileName) 'Save the path and name of the file
FileName = Path.GetFileName(FullyQualfiedPathName)
Else
CancelSave = True
End If
.Dispose()
End With
End If
If (FileName <> String.Empty) Then 'Write the string to the file if the filewas correctly selected
FileStream = File.Open(FullyQualfiedPathName, FileMode.OpenOrCreate, FileAccess.ReadWrite) 'Open the file
Using FileStreamWriter As New StreamWriter(FileStream) 'Create the stream writer
FileStreamWriter.Write(writeData) 'Write the data
FileStream.Close() 'Clse the file
End Using
ElseIf (CancelSave <> True) Then 'Only throw an exception if the user *didn't* cancel the SavefileDialog
Throw New Exception("File stream was nothing", New IOException())
End If
Catch ex As Exception
MessageBox.Show(ex.Message & Environment.NewLine & FullyQualfiedPathName)
End Try
Return True
End Function
One problem I see is that you should be putting your File.Open in a Using block:
Using fs = File.Open(fullyQualfiedPathName, FileMode.OpenOrCreate, FileAccess.ReadWrite)
Using writer As New StreamWriter(fs) 'Create the stream writer
writer.Write(writeData) 'Write the data
'fs.Close() <--- you do not need this line becuase the "Using" block will take care of this for you.
End Using
End Using
I'm not sure if this will resolve your issue because I can't run your code, but the Using block will automatically take care of closing and cleaning up disposable instances like FileStream and StreamWriter, even if an exception is thrown.
By the way, you should use proper naming conventions (lower camel case) for local variables.
I am new to VB.net and I am trying to write a forms app that works with Autodesk Inventor.
Unfortunately, every time I close Inventor, the "Inventor.exe" process still stays. I didn't realize this while debugging and I only realized this when I checked the task manager after the whole system started to lag.
Killing every process with the same name is fairly simple, but the issue is that the end user might have separate documents open in another Inventor window. So I need to write a function that only kills the Inventor processes that don't have a window open.
Public Class Form1
Dim _invApp As Inventor.Application
Dim _started As Boolean = False
Public Sub New()
' This call is required by the designer.
InitializeComponent()
' Add any initialization after the InitializeComponent() call.
Try
_invApp = Marshal.GetActiveObject("Inventor.Application")
Catch ex As Exception
Try
Dim invAppType As Type = _
GetTypeFromProgID("Inventor.Application")
_invApp = CreateInstance(invAppType)
_invApp.Visible = True
'Note: if you shut down the Inventor session that was started
'this(way) there is still an Inventor.exe running. We will use
'this Boolean to test whether or not the Inventor App will
'need to be shut down.
_started = True
Catch ex2 As Exception
MsgBox(ex2.ToString())
MsgBox("Unable to get or start Inventor")
End Try
End Try
End Sub
Another section where I start a process, which is a specific 3D model file.
Public Sub SaveAs(oTemplate As String)
'define the active document
Dim oPartDoc As PartDocument = _invApp.ActiveDocument
'create a file dialog box
Dim oFileDlg As Inventor.FileDialog = Nothing
Dim oInitialPath As String = System.IO.Path.GetFullPath("TemplatesResources\" & oTemplate)
_invApp.CreateFileDialog(oFileDlg)
'check file type and set dialog filter
If oPartDoc.DocumentType = kPartDocumentObject Then
oFileDlg.Filter = "Autodesk Inventor Part Files (*.ipt)|*.ipt"
ElseIf oPartDoc.DocumentType = kAssemblyDocumentObject Then
oFileDlg.Filter = "Autodesk Inventor Assembly Files (*.iam)|*.iam"
ElseIf oPartDoc.DocumentType = kDrawingDocumentObject Then
oFileDlg.Filter = "Autodesk Inventor Drawing Files (*.idw)|*.idw"
End If
If oPartDoc.DocumentType = kAssemblyDocumentObject Then
oFileDlg.Filter = "Autodesk Inventor Assembly Files (*.iam)|*.iam"
End If
'set the directory to open the dialog at
oFileDlg.InitialDirectory = "C:\Vault WorkSpace\Draft"
'set the file name string to use in the input box
oFileDlg.FileName = "######-AAAA-AAA-##"
'work with an error created by the user backing out of the save
oFileDlg.CancelError = True
On Error Resume Next
'specify the file dialog as a save dialog (rather than a open dialog)
oFileDlg.ShowSave()
'catch an empty string in the imput
If Err.Number <> 0 Then
MessageBox.Show("Any changes made from here will affect the original template file!", "WARNING", MessageBoxButtons.OK, MessageBoxIcon.Warning, MessageBoxDefaultButton.Button1, MessageBoxOptions.ServiceNotification)
ElseIf oFileDlg.FileName <> "" Then
Dim MyFile As String = oFileDlg.FileName
'save the file
oPartDoc.SaveAs(MyFile, False)
'open the drawing document
System.Diagnostics.Process.Start(oInitialPath & ".idw")
Dim oFinalPath As String = oPartDoc.FullFileName
MessageBox.Show(oFinalPath, "", MessageBoxButtons.OK, MessageBoxIcon.None, MessageBoxDefaultButton.Button1, MessageBoxOptions.ServiceNotification)
MessageBox.Show("Loaded", "", MessageBoxButtons.OK, MessageBoxIcon.None, MessageBoxDefaultButton.Button1, MessageBoxOptions.ServiceNotification)
Dim oDrawingDoc As DrawingDocument = _invApp.Documents.ItemByName(oInitialPath & ".idw")
'oDrawingDoc.SaveAs()
End If
End Sub
Any help is appreciated.
Thanks
At the end on your form, probably FormClosed, add the following:
Private Sub Form1_FormClosed(sender As Object, e As FormClosedEventArgs) Handles Me.FormClosed
If (_invApp Is Nothing) Then Return ' if empty, then no action needed
_invApp.Quit()
Marshal.ReleaseComObject(_invApp)
_invApp = Nothing
System.GC.WaitForPendingFinalizers()
System.GC.Collect()
End Sub
This should make .NET release and properly dispose the COM Object for Inventor.
And consider declare the Inventor variable and assign Nothing/null, it's safer (avoid mistakes)
Dim _invApp As Inventor.Application = Nothing
I am currently working on a console application to play a freshly created WAV RIFF file, and then delete it. Like I said, it is freshly created, so I need to make sure the file isn't being edited before I start playing it or it will be corrupted. After it plays, I delete it.
Currently, my code looks like this (using System.IO):
Sub Main()
Dim fileName As String
fileName = "C:\temp\Burst\Burst.wav"
While CheckFile(fileName)
End While
Try
My.Computer.Audio.Play(fileName, AudioPlayMode.WaitToComplete)
Catch ex As Exception
Console.WriteLine(ex.Message)
End Try
My.Computer.FileSystem.DeleteFile(fileName)
End Sub
Private Function CheckFile(ByVal filename As String) As Boolean
Try
System.IO.File.Open(filename, IO.FileMode.Open, IO.FileAccess.Read, IO.FileShare.None)
FileClose(1)
Return False
Catch ex As Exception
Return True
End Try
End Function
The function I am using to check if the file is opened was created by sealz. I found it here. Unfortunately, however, this function is causing an exception in that after it runs, the program cannot access the file because it is being used by another process. If I remove this function, the file can be opened, played and deleted.
The exception reads as follows:
An unhandled exception of type'System.IO.IOException' occurred in mscorlib.dll Additionalinformation: The process cannot access the file 'C:\temp\Burst\burst.wav' because it is being used by another process.
So the function that is supposed to help determine if the file is being used, is actually causing the file to be opened. It seems like it isn't closing. Is there anyway I can modify this current function to work properly for my application or are there any other ideas on how to tackle this. Thanks for your time.
-Josh
Here is your problem:
System.IO.File.Open(filename, IO.FileMode.Open, IO.FileAccess.Read, IO.FileShare.None)
FileClose(1)
Return False
A Using will help:
Using _fs as System.Io.FileStream = System.IO.File.Open(filename, IO.FileMode.Open, IO.FileAccess.Read, IO.FileShare.None)
End Using
Return False
File.Open Returns a Filestream, not an Integer needed for FileClose
As far as I get you are trying to check if file exists before playback using System.IO.File.Open however you may do it with File.Exists.
Method File.Exists from System.IO returns true if file exists on path and returns false the otherwise.
Also you are doing it wrong here,
While CheckFile(fileName)
End While
If file is found it will enter into an infinite loop without doing anything other than calling CheckFile repeatedly. If file is not found, it will get out of loop and attempt Audio.Play and FileSystem.DeleteFile and you end up getting a file not found exception.
Here is your code modified and working.
Imports System.IO
Module Module1
Sub Main()
Dim fileName As String
fileName = "C:\temp\Burst\Burst.wav"
While CheckFile(fileName)
Try
My.Computer.Audio.Play(fileName, AudioPlayMode.WaitToComplete)
'Delete statement here if you want file to be deleted after playback
Catch ex As Exception
Console.WriteLine(ex.Message)
End Try
End While
My.Computer.FileSystem.DeleteFile(fileName)
Console.ReadLine()
End Sub
Private Function CheckFile(ByVal filename As String) As Boolean
If (File.Exists(filename)) Then
Return True
Else
Return False
End If
End Function
End Module