Question about SaveFileDialog

Question about SaveFileDialog

• traimo

  Troy,

  If the file does not exist you have to create it. Please use the following code as reference.

  With New SaveFileDialog
  .CheckFileExists = False
  .Filter = "text files(*.txt)|*.txt"
  Dim SaveDlg As DialogResult = .ShowDialog
  If SaveDlg = DialogResult.OK Then
  If Not System.IO.File.Exists(.FileName) Then
  System.IO.File.Create(.FileName) 'Create the file here
  End If
  End If

  Hope this was helpful.

  
  
  

• Savvy

  I made a new application with the following class:
  
  Public Class Form1
  
  Protected b() As Byte
  
  Private Function ReadBytes(ByRef Buffer As Byte(), ByVal FileName As String) As Boolean
  Dim fi As New IO.FileInfo(FileName)
  Dim bytecount As Integer = CInt(fi.Length)
  
  ReDim Buffer(bytecount)
  
  Dim fs As New IO.FileStream(FileName, IO.FileMode.Open, IO.FileAccess.Read)
  Dim br As New IO.BinaryReader(fs)
  
  Buffer = br.ReadBytes(bytecount)
  
  br.Close()
  fs.Close()
  fs.Dispose()
  
  Return True
  End Function
  
  Private Function WriteBytes(ByRef Buffer As Byte(), ByVal FileName As String) As Boolean
  
  Try
  My.Computer.FileSystem.WriteAllBytes(FileName, Buffer, True)
  Return True
  Catch ex As Exception
  MsgBox(ex.Message)
  Return False
  End Try
  
  End Function
  
  Private Function fileLoad() As Boolean
  Dim open As New OpenFileDialog()
  
  With open
  .CheckFileExists = True
  .CheckPathExists = True
  .Filter = "All Files (*.*)|*.*"
  .FilterIndex = 0
  .Title = "Open"
  End With
  
  If open.ShowDialog() <> Windows.Forms.DialogResult.OK Then Exit Function
  'ReadBytes(b, fname)
  Dim b As Byte() = My.Computer.FileSystem.ReadAllBytes(open.FileName)
  End Function
  
  Private Function fileSave() As Boolean
  Dim save As New SaveFileDialog
  
  With save
  .CheckFileExists = False
  .CheckPathExists = True
  .Filter = "All Files (*.*)|*.*"
  .FilterIndex = 0
  .OverwritePrompt = True
  .Title = "Save"
  End With
  
  If save.ShowDialog <> Windows.Forms.DialogResult.OK Then Exit Function
  If Not IO.File.Exists(save.FileName) Then IO.File.Create(save.FileName)
  WriteBytes(b, save.FileName)
  
  Return True
  End Function
  
  Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
  fileLoad()
  End Sub
  
  Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
  fileSave()
  End Sub
  End Class
  
  See if you can get it to work on your machine. I have no clue what I am doing wrong.
  The form has only two controls: 2 Buttons; one labeled Open and the other labeled Save.
  
  Thank you for your continued efforts to resolve my problem.
  
  Enjoy!
  
  
  

• rhapsodyv

  As far as I know the only thing that is accessing the file is my program.
  I tried the code you posted and I got the same message whether the 3rd param was true or false.
  It said it cannot access the file because it is being used by another process. Maybe it has something to do with the way I have opened the file. I used the following function:
  
  Private Function ReadBytes(ByRef Buffer As Byte(), ByVal FileName As String) As Boolean
  Dim fi As New IO.FileInfo(FileName)
  Dim bytecount As Integer = CInt(fi.Length)
  
  ReDim Buffer(bytecount)
  
  Dim fs As New IO.FileStream(FileName, IO.FileMode.Open, IO.FileAccess.Read)
  Dim br As New IO.BinaryReader(fs)
  
  Buffer = br.ReadBytes(bytecount)
  
  br.Close()
  fs.Close()
  fs.Dispose()
  
  Return True
  End Function
  
  That must obviously be inefficient because my WriteBytes function was so. Thanks for all your help.
  
  Enjoy!
  
  
  

• Jesse Blankenbiller

  Does this occur on any file you try and write using this routine

  If you try calling this routine from another very simple program which create a byte array and then tries to write it does this work

  If thr function writes from another very simple application and/or can write using this method then it would indicate there is something in you application that is causing the problem.

  If you can get it to repro - only on this file and from a very simple app calling this function then it may be an issue.

  
  

• pjella

  All the save dialog is doing is giving you a dialog where you can select a filename or enter a filename that you want ot use in you save action. You still need to actually write the action that you want to do.

  So similar to the previous example just using My.Computer.FileSystem.WriteAllText to write the contents of the textbox to the file.

  Public Class Form1

  Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

  With New SaveFileDialog
  .CheckFileExists = False
  .Filter = "text files(*.txt)|*.txt"
  Dim SaveDlg As DialogResult = .ShowDialog
  If SaveDlg = System.Windows.Forms.DialogResult.OK Then
  My.Computer.FileSystem.WriteAllText(.FileName, Textbox1.text, False) '/Write the file with contents
  End If
  End With
  End Sub
  End Class

  
  

• Jelgab

  Wow, talk about recycle - reduce - reuse. This is great. The code worked perfectly. I guess I had two unnecessary functions.
  
  Yeah, and about creating another local byte array, I didn't have that in my normal code. I put it in there trying to figure something out. heh. I originally had: b() = My.Computer.FileSystem.ReadAllBytes(open.FileName).
  I guess since I had the parenthesis after the b it didn't work.
  
  Thanks for your trouble. I appreciate it greatly.
  
  Enjoy!
  
  
  

• George.R.C

  The following works just fine for loading a byte array from a file and saving it back to a file.

  Public Class Form1

  Protected b() As Byte

  Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
  fileLoad()
  End Sub

  Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
  fileSave()
  End Sub

  Private Function fileLoad() As Boolean
  Dim open As New OpenFileDialog()
  With open
  .CheckFileExists = True
  .CheckPathExists = True
  .Filter = "All Files (*.*)|*.*"
  .FilterIndex = 0
  .Title = "Open"
  End With

  If open.ShowDialog() <> Windows.Forms.DialogResult.OK Then Exit Function
  b = My.Computer.FileSystem.ReadAllBytes(open.FileName)
  Return True
  End Function

  Private Function fileSave() As Boolean
  Dim save As New SaveFileDialog
  With save
  .CheckFileExists = False
  .CheckPathExists = True
  .Filter = "All Files (*.*)|*.*"
  .FilterIndex = 0
  .OverwritePrompt = True
  .Title = "Save"
  End With

  If save.ShowDialog <> Windows.Forms.DialogResult.OK Then Exit Function
  My.Computer.FileSystem.WriteAllBytes(save.FileName, b, False)

  Return True
  End Function

  End Class

  In you code in the load event your creating another load byte array called b which will have local scope only and therefore no be accessible in the save routine. The WriteallBytes method call you made had append set to True - my assumption is that for a copy of a file this would be set to false to create a exact copy of the bytes not append them onto existing contents of file.

  This is stripped back and uses just the My.Computer.FileSystem.WriteAllBytes
  

  
  

• greeniguana

  Ok, I got the program to create a file, but it still causes an error this is what i got.
  
  Private Function fileSave() As Boolean
  Dim save As New SaveFileDialog
  'WriteValues()
  Try
  With save
  .CheckFileExists = False
  .CheckPathExists = True
  .Filter = "All Files (*.*)|*.*"
  .FilterIndex = 0
  .OverwritePrompt = True
  .Title = "Save"
  End With
  
  If save.ShowDialog <> Windows.Forms.DialogResult.OK Then Exit Try
  If Not IO.File.Exists(save.FileName) Then IO.File.Create(save.FileName)
  WriteBytes(b, save.FileName)
  Catch ex As Exception
  MsgBox("Failed to save file.", MsgBoxStyle.OkOnly, "Failure")
  End Try
  Return True
  End Function
  
  
  And here is the WriteBytes Function:
  
  Private Function WriteBytes(ByRef Buffer As Byte(), ByVal FileName As String) As Boolean
  Dim fs As New IO.FileStream(FileName, IO.FileMode.Open, IO.FileAccess.Write)
  Dim bw As New IO.BinaryWriter(fs)
  
  bw.Write(Buffer, 0, Buffer.Length)
  
  bw.Close()
  fs.Close()
  fs.Dispose()
  
  Return True
  End Function
  
  In my code b is a byte array that I use to store the bytes of a file in. This process has always worked when I was overwriting a file but now it is giving me trouble. Any ideas
  
  Enjoy!
  
  
  
  Edit: I just found out the error. In my WriteBytes function where I create a new filestream (fs) it says I cannot access the file (to write to it) because it is being used by another process. I added IO.FileShare.Write and it still gives the error. Any Ideas
  
  
  

• Phil Borg

  Things I'd do/try

  1. Find out what has got the file open.

  2. Put some exception handling in you code to identify these problems.

  3. Possibly try a simpler approach if your using My.Computer.FileSystem.WriteAllBytes which has an 3rd parameter append or overwrite.

  Private Function WriteBytes(ByRef Buffer As Byte(), ByVal FileName As String) As Boolean
  Try
  My.Computer.FileSystem.WriteAllBytes(FileName, Buffer, False)
  Return True
  Catch ex As Exception
  MsgBox(ex.Message)
  Return False
  End Try
  End Function

  I suppose 1 and 2 are the most important.

  
  

• MiggyE

  You can actually reduce it further if you really wanted to and all those properties can be set at design time if your really wanted by dropping those two controls on the form. Potentially reducing the code down to 4 lines of actual code.

  Public Class Form1

  Protected b() As Byte

  Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
  Dim open As New OpenFileDialog()
  With open
  .CheckFileExists = True
  .CheckPathExists = True
  .Filter = "All Files (*.*)|*.*"
  .FilterIndex = 0
  .Title = "Open"
  End With

  If open.ShowDialog() <> Windows.Forms.DialogResult.OK Then Exit Function
  b = My.Computer.FileSystem.ReadAllBytes(open.FileName)
  End Sub

  Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
  Dim save As New SaveFileDialog
  With save
  .CheckFileExists = False
  .CheckPathExists = True
  .Filter = "All Files (*.*)|*.*"
  .FilterIndex = 0
  .OverwritePrompt = True
  .Title = "Save"
  End With

  If save.ShowDialog <> Windows.Forms.DialogResult.OK Then Exit Function
  My.Computer.FileSystem.WriteAllBytes(save.FileName, b, False)
  End Sub
  End Class
  

  
  
• Question about SaveFileDialog