Copy and Delete File Leaves Zero Length File at Source - vb.net

I'm trying to copy a file from one directory to another. After the copy, I want to delete the original file. The expected result is that the source file no longer exists and the destination file does exist. The actual result is that the destination file exists and that an empty source file exists. Watching the directory during execution, the source file initially disappears then upon exiting the program it reappears with a length of zero.
Here's sample code:
Imports System.IO
Module Module1
Sub Main()
Dim sourceFileName As String = "c:\TestDir\source\TestFile.txt"
Dim destFileName As String = "c:\TestDir\destination\TestFile.txt"
System.IO.File.Copy(sourceFileName, destFileName)
System.IO.File.Delete(sourceFileName)
End Sub
End Module
If I were to remove the System.IO.Copy, the zero-length file does not appear. So it seems to have something to do with the combination of copying and deleting.
Are my expectations amiss? I realize I can delete the destination if it exists then Move the file, but I would like to understand why my sample does not work as I expect it. Thanks for any insight.

Try using the FileSystem.DeleteFile method from here:
https://learn.microsoft.com/en-us/dotnet/api/microsoft.visualbasic.fileio.filesystem.deletefile?view=netframework-4.7.2
This should completely remove the file.

Has the Read-Only attribute been applied to your test file? If so, you can try something like this:
File.Copy(sourceFileName, destFileName)
File.SetAttributes(sourceFileName, FileAttributes.Normal);
File.Delete(sourceFileName)
Is there a reason you're not just using File.Move?

Related

Setting Directories and the If Len(Dir(... statement in VBA

I have a file exists under this path:
//path/folder1/folder2/datafile.gdp
It is an input to an external program being called from vba in this manner:
Sub RunProgram()
Dim wsh As Object
SetCurrentDirectory "\\path\"
ChDir "\\path\folder1\folder2\" 'Set Directory
Set wsh = VBA.CreateObject("WScript.Shell")
check = CurDir
Statusnum = wsh.Run(Command:="program.exe ""\\path\folder1\folder2\datafile.gdp""", WindowStyle:=1, waitonreturn:=True)
But on the final line, including \path\folder1\folder2\ before the input file name appears to cause the external program to want to write some files into a duplicated directory that doesn't exist, causing an error. It used to work in this format before the .exe was updated by an external company. It now wants to write some files here, all prefixed with the name of my input file:
\\path\folder1\folder2\PATH\FOLDER1\FOLDER2\
Hoping to fix this, I changed the final line of the code to this, following some comments on a previous post here on SO:
Statusnum = wsh.Run(Command:="program.exe ""datafile.gdp""", WindowStyle:=1, waitonreturn:=True)
Since the directory is set correctly prior to calling the .exe, I thought removing the path for the input file would solve the issue.
The program now launches, but doesn't appear to load the input file with it and no longer runs calculations automatically in the background as it should. Instead, it launches and the main .exe window pops up to the user as if it had just been launched for setting up a new project, calculations don't occur automatically.
To check which directory the VBA code was try to pull my datafile.gdp from, I created these loops directly before calling the .exe:
If Len(Dir("\\path\folder1\folder2\datafile.gdp")) = 0 Then
FileIsMissing1 = True 'I use Excel-VBA watches to break if true
End If
If Len(Dir("datafile.gdp")) = 0 Then
FileIsMissing2 = True
End If
Bizarrely, neither of these loops causes a break. The file only exists in
\\path\folder1\folder2\datafile.gdp
Not in the duplicated directory... so why are both of these statements satisfied? Does entering the directory make no difference even when the current directory has been set? The current directory seems to be impacting the line:
Statusnum = wsh.Run(Command:="program.exe ""\\path\folder1\folder2\datafile.gdp""", WindowStyle:=1, waitonreturn:=True)
But not these if loops, and I'm not sure why.

Better Way to Copy Move Rename File, Visual Basic (VS 2012 V11)

I want to copy, rename, and move a file to a new location. According to http://msdn.microsoft.com/en-us/library/36xbexyf(v=vs.90).aspx the following code should do so:
This example copies the file Test.txt to the directory TestFiles2 and
renames it NewFile.txt.
My.Computer.FileSystem.CopyFile _
("C:\UserFiles\TestFiles\test.txt", _
"C:\UserFiles\TestFiles2", "NewFile.txt", FileIO.UICancelOption.DoNothing)
However, when I type this code it only sees the "NewFile.txt" parameter as the Boolean parameter that handles overwrites. I believe this is a mistake on the websites part.
If I can't use "My.Computer.FileSystem.CopyFile" (unless I am doing something wrong) to copy rename and move a file, is there a better way then this:
' Rename the file to be copied the name you want it to be in the new location
My.Computer.FileSystem.RenameFile("C:\OriginalFile.txt", "OriginalFileTemporaryName.txt")
' Copy the file to the new location and overwrite if it exists there
My.Computer.FileSystem.CopyFile ("C:\OriginalFileTemporaryName.txt", "C:\UserFiles\TestFiles2", True)
' Rename the original file back to it's original name
My.Computer.FileSystem.RenameFile("C:\OriginalFileTemporaryName.txt", "OriginalFile.txt")
The problem I have with the above is that I might end up renaming the original file a temporary name that already exists in the original files location. I want to avoid that. I also do not want to rename the copied file in the destination folder because I do not see an option to force an overwrite for "My.Computer.FileSystem.RenameFile"
Is this even a half decent solution?
Is there not a better way to do this?
I think you have syntax error. You are trying to give the target file name as two parameters - directory name and file name, when you should give both as one string.
My.Computer.FileSystem.CopyFile ("C:\UserFiles\TestFiles\test.txt", "C:\UserFiles\TestFiles2\NewFile.txt")
Like that. Third parameter could be boolean (True/False) - whether or not you wouldd like to overwrite the target file if it exists.
If you want to first check whether the file exists, take a look at System.IO.File class, it has "Exists" method, which accepts file name and returns boolean. It has also methods to manipulate files which you can use instead of FileSystem class, although there is no performance advantage.
It certainly looks like a mistake on the website. That shouldn't stop us, though; just put the directory and filename into the same parameter:
My.Computer.FileSystem.CopyFile("C:\UserFiles\TestFiles\test.txt", "C:\UserFiles\TestFiles2\NewFile.txt", FileIO.UICancelOption.DoNothing)
(If you want to force an overwrite, change the third parameter to True. I don't know that you can overwrite and pass CancelOption.DoNothing in the same call.)

Let VB Form prepare working environment in chosen directory

I am working on a GUI for a simulation program. The simulation program is a single .exe which is driven by an input file (File.inp placed in the same directory).
The Original.inp file functions as a template from which the form reads all the values into an array. Then it changes these values reflecting the changes done by the user in the form. After that it writes all the new values to File.inp.
By pushing the "Run" button the Simulation.exe file is executed.
The folder structure looks like this:
root
|
|---input
| |
| |--Original.inp
|
|---GUI.exe
|---Simulation.exe
|---File.inp
Ideally I would supply only the GUI, the user would select the working directory and then the GUI.exe would create an input folder and extract the Original.inp and Simulation.exe in the appropriate locations. So far I have only managed to include Original.inp and Simulation.exe as "EmbeddedResources" in my VB project and I have let my code create an input folder in the working directory chosen by the user.
Can someone please explain to me how I can extract the .inp and .exe file into the correct directories? I've searched on google, tried File.WriteAllBytes and Filestream.WriteByte but did not get the desired results.
The problem with File.WriteAllBytes was that I could not point to the embedded resource ("Simulation.exe is not a member of Resources" and with Filestream.WriteByte I got a 0 kb file.
The question commenters are correct, this is probably a task best left for a setup program. However, that having been stated, in the interest of answering the question as asked I offer the following approach.
Contrary to your supposition in your question comment, you do need to "read" the embedded resource from the GUI's executable file, since it's an embedded resource and not an external resource. It won't magically extract itselt from the executable file. You need to do the manual read from the assembly and write to your specified locations. To do this, you need to read the resource using .Net Reflection, via the currently executing assembly's GetManifestResourceStream method.
The Simulation.exe file is a binary file so it must be handled as such. I assumed that the Orginal.inp file was a text file since it afforded the opportunity to demonstrate different types of file reads and writes. Any error handling (and there should be plenty) is omitted for brevity.
The code could look something like this:
Imports System.IO
Imports System.Reflection
Module Module1
Sub Main()
'Determine where the GUI executable is located and save for later use
Dim thisAssembly As Assembly = Assembly.GetExecutingAssembly()
Dim appFolder As String = Path.GetDirectoryName(thisAssembly.Location)
Dim fileContents As String = String.Empty
'Read the contents of the template file. It was assumed this is in text format so a
'StreamReader, adept at reading text files, was used to read the entire file into a string
'N.B. The namespace that prefixes the file name in the next line is CRITICAL. An embedded resource
'is placed in the executable with the namespace noted in the project file, so it must be
'dereferenced in the same manner.
Using fileStream As Stream = thisAssembly.GetManifestResourceStream("SOQuestion10613051.Original.inp")
If fileStream IsNot Nothing Then
Using textStreamReader As New StreamReader(fileStream)
fileContents = textStreamReader.ReadToEnd()
textStreamReader.Close()
End Using
fileStream.Close()
End If
End Using
'Create the "input" subfolder if it doesn't already exist
Dim inputFolder As String = Path.Combine(appFolder, "input")
If Not Directory.Exists(inputFolder) Then
Directory.CreateDirectory(inputFolder)
End If
'Write the contents of the resource read above to the input sub-folder
Using writer As New StreamWriter(Path.Combine(inputFolder, "Original.inp"))
writer.Write(fileContents)
writer.Close()
End Using
'Now read the simulation executable. The same namespace issues noted above still apply.
'Since this is a binary file we use a file stream to read into a byte buffer
Dim buffer() As Byte = Nothing
Using fileStream As Stream = thisAssembly.GetManifestResourceStream("SOQuestion10613051.Simulation.exe")
If fileStream IsNot Nothing Then
ReDim buffer(fileStream.Length)
fileStream.Read(buffer, 0, fileStream.Length)
fileStream.Close()
End If
End Using
'Now write the byte buffer with the contents of the executable file to the root folder
If buffer IsNot Nothing Then
Using exeStream As New FileStream(Path.Combine(appFolder, "Simulation.exe"), FileMode.Create, FileAccess.Write, FileShare.None)
exeStream.Write(buffer, 0, buffer.Length)
exeStream.Close()
End Using
End If
End Sub
End Module
You will also have to add logic to determine if the files have been extracted so it doesn't happen every time the GUI is invoked. That's a big reason why an installation program might be the correct answer.

vb.net application works with files dragged onto the exe, but crashes if there's a space in the file's path

I'm developing an application in vb.net. You drag any type of file onto the exe, and a window pops up with some options for the file, then it saves the file to a different location, works some SQL magic, etc. It works great for the most part.
The only issue I've found is that if the path of the file contains any spaces, the application will crash immediately with the error window: http://i.stack.imgur.com/mVamO.png
I'm using:
Private filename as String = Command$
This is located right inside my form's class declaration, not within a sub/function.
Without this line, my program runs fine (although useless, without accessing the file).
I've also tried (I think this was it, I don't have the code with me at the moment):
Private filename as String = Environment.CommandLine
And it had the same issue.
So, in vb.net, is there a way to drag a file onto an exe and use that path name, even if there are spaces in the path name?
Windows will put double-quotes around the passed command line argument if the path to the dragged file contains spaces. Trouble is, you are using an ancient VB6 way to retrieve the argument, you see the double quotes. Which .NET then objects against, a double quote is not valid in a path name. Use this:
Dim path = Command$.Replace("""", "")
Or the .NET way:
Sub Main(ByVal args() As String)
If args.Length > 0 then
Dim path = args(0)
MsgBox(path)
'' do something with it..
End If
End Sub
If possible, do post your code as it's pretty much anything that can go wrong. Normally, after receiving CommandLine Arg, I would try to use a System.IO.File wrapper and use built-in mechanisms to verify file and then proceed with it further using IO as much as possible. If you are attempting to directly manipulate the file, then the spaces might become an issue.
In addition, there is a way to convert long file path + name to old DOS’s 8.3 magical file path + name. However, I’ll go into R&D after I see what you are doing in code.

Making folder and copying file

I want my application to look for a file in drive C's specific folder (say C:\myFolder\abc.mdb), if found just give a message if not, make the folder in drive C:\ and then copy the file.
How to do this?
Thanks
Furqan
You could use the File, Directory, and Path objects in the System.IO as shown below:
Imports System.IO
...
Dim path As String = "C:\myFolder\abc.mdb"
If File.Exists(path) Then
'TODO write code to create message'
Else
Dim folder As String = Path.GetDirectoryName(path)
If Not Directory.Exists(folder) then
Directory.CreateDirectory(folder)
End If
'TODO code to copy file from current location to the newly created directory path'
'i.e. File.Copy(FileToCopy, NewCopy)'
End If
I know this post is kind of old. I just wanted to update.
The quickest shortcut that will also create the Destination directory structure and in one line. Use Computer.FileSystem.CopyFile instead of System.IO.
My.Computer.FileSystem.CopyFile(sSourcefile, sDestinationfile)