I am using VB.NET (VS-2012), I use to scan documents in my applicant software. When i scan document i resize the scanned image and save it over the original file. When the user scan all the required documents then the use click the save button. After clicking the save button the application upload the images to database and try to delete the locally created files but stuck with the error that the file is in use.
I am using the following code...
Tw.Init(Me.Handle)
If (Not msgfilter) Then
Me.Enabled = False
msgfilter = True
Application.AddMessageFilter(Me)
End If
If SelectScanner Then
Tw.Select()
SelectScanner = False
End If
Tw.Acquire(chkScanner.Checked)
This function listens the event triggered by tw.acquire()
Public Function PreFilterMessage(ByRef m As Message) As Boolean Implements IMessageFilter.PreFilterMessage
Try
Dim cmd As TwainCommand = Tw.PassMessage(m)
If (cmd = TwainCommand.Not) Then
Return False
End If
Select Case cmd
Case TwainCommand.CloseRequest
EndingScan()
Tw.CloseSrc()
Case TwainCommand.CloseOk
EndingScan()
Tw.CloseSrc()
Case TwainCommand.DeviceEvent
Case TwainCommand.TransferReady
Dim pics As ArrayList = Tw.TransferPictures()
EndingScan()
Tw.CloseSrc()
For i = 0 To pics.Count - 1 Step 1
flName = TempPath & "\" & GetNextFileName(TempPath, lstDocType.Items(cboDocTypes.SelectedIndex).ToString)
Dim img As IntPtr = CType(pics(i), IntPtr)
SaveImage(img)
lstDocuments.Items.Add(flName)
lstDocType.Items.Add(GetDocType(cboDocTypes.SelectedIndex))
SetItemData(lstDocuments, lstDocuments.Items.Count - 1, GetItemData(lstApplicants, lstApplicants.SelectedIndex))
Try
lstDocuments.SelectedIndex = lstDocuments.Items.Count - 1
Catch ex As Exception
End Try
Dim Original As Image = Image.FromFile(flName)
Dim Resized As Image = ResizeImage(Original, New Size(1024, 1407), False)
Original.Dispose()
Resized.Save(flName, ImageFormat.Jpeg)
Resized.Dispose()
img = Nothing
pics = Nothing
Next
Tw.Dispose()
Case 0
Return False
End Select
Return True
Catch ex As Exception
Return False
MsgBox(ex.Message)
End Try
End Function
In this given function you can see that the image is resized and the original image is replaced with the resized one. And then the resize object is disposed but when the software try to delete the image after uploading it to database, an error occurs.
I don't know whats the problem.
Related
When image field property in class is set with the image raw format of the same image from my database in picture box, it always throws this exception. In contrast, if the image in the picture box has been updated with one I select from my local PC directory, the update function work fine.
Below is my code:
Try
With mEmployee
If Miscellaneous.GetImageName(ofdPhoto).ToLower = "No_Photo.jpg".ToLower Then
.Image = Nothing
Else
Dim stream As New MemoryStream
pbImage.Image.Save(stream, pbImage.Image.RawFormat)
.Image = stream.GetBuffer()
End If
End With
Catch ex As Exception
MessageBox.Show(ex.Message)
End Try
Now everything has solved. This GDI+ generic error caused by the picture box itself. Actually, When I bound the record with image from the database and update that record without updating the image in the PictureBox, the image field has been set with old byte() data from the box, and that caused the error.
To solve this, I have declare a byte() type variable to store the temp image byte() data from the database, and when update, if the image has not been changed it will be set with the data from that variable.
This is my code that solve everything:
Try
If Miscellaneous.GetImageName(ofdPhoto).ToLower = "No_Photo.jpg".ToLower Then
.Image = Nothing
Else
If isImageChanged = True Then
Dim stream As New MemoryStream
pbImage.Image.Save(stream, pbImage.Image.RawFormat)
.Image = stream.GetBuffer()
isImageChanged = False
ElseIf isRemoveImage = True Then
.Image = Nothing
isRemoveImage = False
Else
.Image = tempImage
End If
End If
Catch ex As Exception
MessageBox.Show(ex.Message)
End Try
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 know this question has been asked before, but my situation is a bit wonky.
Basically, I'm trying to print a PDF file that I've generated using a previous Windows Form. I can find the file no problem, and I used the following code which I found off MSDN's help forums:
Dim p As New System.Diagnostics.ProcessStartInfo()
p.Verb = "print"
p.WindowStyle = ProcessWindowStyle.Hidden
p.FileName = "C:\534679.pdf" 'This is the file name
p.UseShellExecute = True
System.Diagnostics.Process.Start(p)
So far so good, but everytime I press the button to run this code, it keeps asking me to save it as a PDF file instead, as shown below:
I've also tried adding a PrintDialog to the Windows Form, getting it to pop up, and I can select the printer I want to use from there, but even after selecting the printer it still asks me to print to PDF Document instead.
What am I doing wrong?
To print massive PDF documents with VB.Net you can use LVBPrint and run it via command line:
http://www.lvbprint.de/html/gsbatchprint1.html
For Example:
C:\temp\gsbatchprint64\gsbatchprintc.exe -P \\server\printer -N A3 -O Port -F C:\temp\gsbatchprint64\Test*.pdf -I Tray3
I use the following function in my application:
' print a pdf with lvbrint
Private Function UseLvbPrint(ByVal oPrinter As tb_Printer, fileName As String, portrait As Boolean, sTray As String) As String
Dim lvbArguments As String
Dim lvbProcessInfo As ProcessStartInfo
Dim lvbProcess As Process
Try
Dim sPrinterName As String
If portrait Then
lvbArguments = String.Format(" -P ""{0}"" -O Port -N A4 -F ""{1}"" -I ""{2}"" ", sPrinterName, fileName, sTray)
Else
lvbArguments = String.Format(" -P ""{0}"" -O Land -N A4 -F ""{1}"" -I ""{2}"" ", sPrinterName, fileName, sTray)
End If
lvbProcessInfo = New ProcessStartInfo()
lvbProcessInfo.WindowStyle = ProcessWindowStyle.Hidden
' location of gsbatchprintc.exe
lvbProcessInfo.FileName = LvbLocation
lvbProcessInfo.Arguments = lvbArguments
lvbProcessInfo.UseShellExecute = False
lvbProcessInfo.RedirectStandardOutput = True
lvbProcessInfo.RedirectStandardError = True
lvbProcessInfo.CreateNoWindow = False
lvbProcess = Process.Start(lvbProcessInfo)
'
' Read in all the text from the process with the StreamReader.
'
Using reader As StreamReader = lvbProcess.StandardOutput
Dim result As String = reader.ReadToEnd()
WriteLog(result)
End Using
Using readerErr As StreamReader = lvbProcess.StandardError
Dim resultErr As String = readerErr.ReadToEnd()
If resultErr.Trim() > "" Then
WriteLog(resultErr)
lvbProcess.Close()
Return resultErr
End If
End Using
If lvbProcess.HasExited = False Then
lvbProcess.WaitForExit(3000)
End If
lvbProcess.Close()
Return ""
Catch ex As Exception
Return ex.Message
End Try
End Function
I discourage on using AcrRd32.exe as it doesn't work with massive printings.
First, to be able to select a Printer, you'll have to use a PrintDialog and PrintDocument to send graphics to print to the selected printer.
Imports System.Drawing.Printing
Private WithEvents p_Document As PrintDocument = Nothing
Private Sub SelectPrinterThenPrint()
Dim PrintersDialog As New PrintDialog()
If PrintersDialog.ShowDialog(Me) = System.Windows.Forms.DialogResult.OK Then
Try
p_Document = New PrintDocument()
PrintersDialog.Document = p_Document
AddHandler p_Document.PrintPage, AddressOf HandleOnPrintPage
Catch CurrentException As Exception
End Try
End If
End Sub
Private Sub HandleOnPrintPage(ByVal sender As Object, ByVal e As PrintPageEventArgs) Handles p_Document.PrintPage
Dim MorePagesPending As Boolean = False
'e.Graphics.Draw...(....)
'e.Graphics.DrawString(....)
' Draw everything...
If MorePagesPending Then
e.HasMorePages = True
Else
e.HasMorePages = False
End If
End Sub
That's what I'm doing since I usually have custom objects to print.
But to print PDF Files, you must understand that PDF means absolutely nothing to dotNet. Unlike common images like Bitmaps (.bmp) or Ping images (.png) the dotNet doesn't seem to have any inbuilt parser/decoder for reading, displaying and printing PDF files.
So you must use a third party application, thrid party library or your own custom PDF parser/layout generator in order to be able to send pages to print to your printer.
That's why you can't launch a hidden (not visible) process of Acrobat Reader with the command "print". You won't be able to select a printer but will direct to the default one instead !
You can however launch the Acrobat Reader process just to open the file, and do the printing manipulations (select a printer) inside Acrobat Reader (you're outside dotNet coding now)
A workaround for your may aslo to select another default printer by opening Acrobat Reader, and print one blank page on an actual working printer. This should deselect your FoxIt thing in favour of an actual printer..
This code will help you to print in a specific printer.
The sample print a file using a ProcessStartInfo and a specific printer you can change the printer to use in the process.
If the print process is not finished after 10 seconds we kill the print process.
'Declare a printerSettings
Dim defaultPrinterSetting As System.Drawing.Printing.PrinterSettings = Nothing
Private Sub cmdPrint_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdPrint.Click
Try
dim fileName As String = "C:\534679.pdf"
'Get de the default printer in the system
defaultPrinterSetting = DocumentPrinter.GetDefaultPrinterSetting
'uncomment if you want to change the default printer before print
'DocumentPrinter.ChangePrinterSettings(defaultPrinterSetting)
'print your file
If PrintFile(fileName, defaultPrinterSetting) then
msgbox ("your print file success message")
else
msgbox ("your print file failed message")
end if
Catch ex As Exception
mssbox(ex.Message.toString)
End Try
End Sub
Public NotInheritable Class DocumentPrinter
Shared Sub New()
End Sub
Public Shared Function PrintFile(ByVal fileName As String, printerSetting As System.Drawing.Printing.PrinterSettings) As Boolean
Dim printProcess As System.Diagnostics.Process = Nothing
Dim printed As Boolean = False
Try
If PrinterSetting IsNot Nothing Then
Dim startInfo As New ProcessStartInfo()
startInfo.Verb = "Print"
startInfo.Arguments = defaultPrinterSetting.PrinterName ' <----printer to use----
startInfo.FileName = fileName
startInfo.UseShellExecute = True
startInfo.CreateNoWindow = True
startInfo.WindowStyle = ProcessWindowStyle.Hidden
Using print As System.Diagnostics.Process = Process.Start(startInfo)
'Close the application after X milliseconds with WaitForExit(X)
print.WaitForExit(10000)
If print.HasExited = False Then
If print.CloseMainWindow() Then
printed = True
Else
printed = True
End If
Else
printed = True
End If
print.Close()
End Using
Else
Throw New Exception("Printers not found in the system...")
End If
Catch ex As Exception
Throw
End Try
Return printed
End Function
''' <summary>
''' Change the default printer using a print dialog Box
''' </summary>
''' <param name="defaultPrinterSetting"></param>
''' <remarks></remarks>
Public Shared Sub ChangePrinterSettings(ByRef defaultPrinterSetting As System.Drawing.Printing.PrinterSettings)
Dim printDialogBox As New PrintDialog
If printDialogBox.ShowDialog = Windows.Forms.DialogResult.OK Then
If printDialogBox.PrinterSettings.IsValid Then
defaultPrinterSetting = printDialogBox.PrinterSettings
End If
End If
End Sub
''' <summary>
''' Get the default printer settings in the system
''' </summary>
''' <returns></returns>
''' <remarks></remarks>
Public Shared Function GetDefaultPrinterSetting() As System.Drawing.Printing.PrinterSettings
Dim defaultPrinterSetting As System.Drawing.Printing.PrinterSettings = Nothing
For Each printer As String In System.Drawing.Printing.PrinterSettings.InstalledPrinters
defaultPrinterSetting = New System.Drawing.Printing.PrinterSettings
defaultPrinterSetting.PrinterName = printer
If defaultPrinterSetting.IsDefaultPrinter Then
Return defaultPrinterSetting
End If
Next
Return defaultPrinterSetting
End Function
End Class
I used this code to print my PDF files on VB NET:
Dim PrintPDF As New ProcessStartInfo
PrintPDF.UseShellExecute = True
PrintPDF.Verb = "print"
PrintPDF.WindowStyle = ProcessWindowStyle.Hidden
PrintPDF.FileName = dirName & fileName 'fileName is a string parameter
Process.Start(PrintPDF)
When you do this, process remains open with a adobe reader window that users have to close manually. I wanted to avoid user's interaction, just want them to get their documents. So, I added a few code lines to kill process:
Private Sub killProcess(ByVal processName As String)
Dim procesos As Process()
procesos = Process.GetProcessesByName(processName) 'I used "AcroRd32" as parameter
If procesos.Length > 0 Then
For i = procesos.Length - 1 To 0 Step -1
procesos(i).Kill()
Next
End If
End Sub
If you put the kill process method right after the print method you won't get your document printed (I guess this is because process is killed before it is sent to printer). So, between these 2 methods, I added this line:
Threading.Thread.Sleep(10000) ' 10000 is the milisecs after the next code line is executed
And with this my code worked as I wanted. Hope it helps you!
I started making a file manager which scans a folder selected by user through folderbrowserdialog in vb.net, extract the extentions of every file in every directory or subdirectory using GetFiles() Method with SearchOption.AllDirectories. I am having an UnauthorizedAccessException when it scans the Recycle Bin Folder in logical drive whereas i have seen Softwares like WinRar or R-Studio Scanning and showing every directory without having an exception or error. Following is my code:
Public Sub WriteExtentionsToFile()
Try
Title_Window.FolderBrowserDialog.ShowDialog()
Dim Path As String = Title_Window.FolderBrowserDialog.SelectedPath
'Getting FilesNames
Dim FileNames As String() = GetFilesNames(Path)
Title_Window.LblStatusBar.Text = "File Names Saved"
Dim MaximumForProgressBar As Integer = FileNames.Length
Title_Window.ToolStripProgressBar1.Maximum = MaximumForProgressBar
Title_Window.ToolStripProgressBar1.Step = 1
'Getting Extentions
Dim ExtentionsList As New List(Of String)
For Each item In FileNames
ExtentionsList.Add(System.IO.Path.GetExtension(item))
Next
'Deleting Duplicate Extentions
Dim NoDuplicateExtentionList As New List(Of String)
Dim ExtentionReadFromFile As String() = ReadExtentionsFromFile()'Another Function in my Class Which Reads previously saved extentions in a file and store them in an array
For Each item In ExtentionReadFromFile
NoDuplicateExtentionList.Add(item)
Next
For Each E In ExtentionsList
Dim LastIndexOfDot As Integer = E.LastIndexOf(".")
E = E.Remove(0, LastIndexOfDot + 1)
If NoDuplicateExtentionList.Contains(E.ToLower) = False Then
NoDuplicateExtentionList.Add(E.ToLower)
My.Computer.FileSystem.WriteAllText("d:\ExtentionsList.txt", E.ToString & vbCrLf, True)
End If
Next
MessageBox.Show("Writing Process Completed", "Success")
Catch ex As UnauthorizedAccessException
Dim Buttons As MessageBoxButtons = MessageBoxButtons.AbortRetryIgnore
Dim result As DialogResult
MessageBox.Show(ex.ToString, "Access Denied", Buttons)
If result = Windows.Forms.DialogResult.Ignore Then
'What should be Done Here????
ElseIf result = Windows.Forms.DialogResult.Abort Then
'What should be Done Here????
Else
'What should be Done Here????
End If
Catch ex As Exception
MessageBox.Show(ex.ToString)
End Try
End Sub
What should be the solution for thsi problem? Is this about getting the permissions through FileIoPermission Class or something else??
I'm writing a little program where I select a picture through an open file dialogue. When I selected a picture I want it to overwrite the current picture and display the new image. Now I don't have any problems with picking an image with a different extension. So when I currently have a .png I can select a .jpg but when I choose an image with the same extension as the current image I get an error:
The process cannot access the file 'C:\Users....\woontypeimages\chalet_foto.jpg' because it is being used by another process.
If ofd.ShowDialog() = Windows.Forms.DialogResult.OK Then
Dim sFilename As String = cboWoningtypesWoningtype.SelectedItem.ToString & "_foto" & System.IO.Path.GetExtension(ofd.FileName)
System.IO.File.Copy(ofd.FileName, Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData) & "\Camping Relaxx\woontypeimages\" & sFilename, True)
txtWoningtypesFoto.Text = sFilename
updateImages()
End If
Private Sub updateImages()
Try
picFoto.Image = Nothing
txtWoningtypesFoto.BackColor = clrReadonly
txtWoningtypesFoto.ForeColor = Color.Black
picFoto.Image = System.Drawing.Image.FromFile(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData) & "\Camping Relaxx\woontypeimages\" & txtWoningtypesFoto.Text)
Catch ex As Exception
txtWoningtypesFoto.BackColor = clrError
txtWoningtypesFoto.ForeColor = Color.White
End Try
Try
picGrondplan.Image = Nothing
txtWoningtypesGrondplan.BackColor = clrReadonly
txtWoningtypesGrondplan.ForeColor = Color.Black
picGrondplan.Image = System.Drawing.Image.FromFile(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData) & "\Camping Relaxx\woontypeimages\" & txtWoningtypesGrondplan.Text)
Catch ex As Exception
txtWoningtypesGrondplan.BackColor = clrError
txtWoningtypesGrondplan.ForeColor = Color.White
End Try
End Sub
If anyone could help me I would be pleased
Thanks in advance
Instead of worrying about Dispose() you can instead use the Load(string) method of the PictureBox which won't lock the file.
Me.PictureBox1.Load("C:\test.png")
Use these :
picFoto.Image.Dispose()
picGrondplan.Image.Dispose()
instead of :
picFoto.Image = Nothing
picGrondplan.Image = Nothing
The Image.FromFile method maintains a lock on the source file until the image has been disposed. Setting an object to nothing does not immediately dispose it - the garbage collector will take care of that in its own time (which might well not be until you've closed the form with the picture box on). Dispose is required to immediately free the file handle.