The VB.Net program in question creates several files, adds them into a zip file (using DotNetZip), and saves the zip file into a given directory (which the user chooses). This comes out just fine. But when I use it to save directly to my USB flash drive, I can't eject the drive without shutting down the program first.
I've tried disposing the zip object (from the DotNetZip library), doesn't work. I also tried setting FileIO.FileSystem.CurrentDirectory to somewhere else on the machine, still no.
In your last comment you've said that calling the 'Close' outside of the Try Catch sorted your problem, I'd recomend using a "Using" stament insted. This will close/dispose of your StreamWriter 100% of the time no matter what happens.
http://msdn.microsoft.com/en-us/library/htd05whh.aspx
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I have a single command line windows executable that has many options built into this exe file.
Eg:
(It can take screenshot)
ToolGo.exe printscreen c:\temp\filename.jpg yyyymmdd
(It can show up)
ToolGo.exe showIP machineA
I want to write another command line application, possibly in .net , where it can embed/build a wrapper around this ToolGo.exe file into my application without the user be able to use the ToolGo.exe, and also users can only access one function of this main exe file.
In the example I want this other tool to access only the print screen function in this new exe file.
The new application will have this:
Tool2go.exe printscreen c:\temp\filename.jpg yyyymmdd
But if someone types the following, it will not work:
Tool2go.exe showIP machineA
Or
ToolGo.exe showIP machineA
Any ideas how I can write this code to do this in a .net command line application?
This is a multi-part question, so I'll just give the main part of the issue as the answer with suggestions on handling the rest.
You can embed a .exe into your program by clicking on Properties and navigating the the Resources section, and adding that .exe to it.
After that, it's just a matter of extracting it locally so you can pass your commands to it, and handle it's responses. (I'm not really aware of any way to do so w/out first extracting the. exe; the .exe itself needs to run somehow after all).
To extract the embedded .exe, you do this:
' Extract the MyProgram resource (i.e. your .exe)
Dim b() As Byte = My.Resources.MyProgram
' Write it to the user's Temp folder
File.WriteAllBytes(Environment.ExpandEnvironmentVariables("%TEMP%\MyProgram.exe"), b)
By extracting it to the user's Temp folder, you can pass it your commands, and since it's 'out of sight' the user probably won't even know it's there to directly use it themselves, unless they're a bit more advanced and visit their Temp folder often. You can slightly help to avoid this, but extracting the .exe when your program starts, and then deleting it when it exits, so it only exists on the user's system while your program is running.
As far as what the user can and cannot type in order to pass to the program, you can simply handle the filtering with your program; since your program is the one passing the commands to the .exe, just don't pass any commands that you don't allowed, and pass the ones you do want allowed.
I have a program that uploads .txt or .rje files from a folder. Now when you put any other file format into the folder, like .jar, then the application crashes.
Now I cannot change the mechanics of the application, so I would like to know if there is a type of program/script that I can use that monitors the folder for any files that are non-txt/rje and then move them out of the folder once they are put there...
Is this possible using a script? (I do not want to use a .exe application to do this...not allowed to install 3rd party software onto the server this folder exists...)
Thank you
Your solution won't work as you have a race condition between the program doing the upload and the one doing the deletion. If upload runs first it still crashes.
The correct solution is to modify the upload program to cope with this scenario.
If that is not possible then the only safe work around would be to use a new folder to drop the files in, have a script run that constantly scans the folder and if a new file appears either move it to the processing folder or deletes it as appropriate.
(For the actual detection that's not my area of expertise but the simplest would be to have a bat file that just runs periodically (or even just runs once and loops with a wait, check, move, wait, check, move, etc) and processes everything in the folder when it runs).
I want to create a file on Mac OS X (10.6) that will be deleted automatically when my process goes away. Is this possible? It would be very handy for a file locking scheme I am implementing. Preferably as a Cocoa or Carbon call.
I know that on Windows, this is possible. It's a very neat feature, but I don't know if it is something that needs to be supported by the file system.
On win32 you can call CreateFile with FILE_FLAG_DELETE_ON_CLOSE.
In .net you can create a FileStream with FileOptions.DeleteOnClose as argument.
If you are writing your own program, you could use tmpfile() call.
It creates a temporary file that get removed automatically on program termination.
You could have your app delegate to create and delete the file via the NSApplicationDelegate, however, the file would remain there if the user force quits/shut down. If force quitting is not part of your concern, then this should work. If not, you can create a simple launch agent that checks if your process exists, and if not, delete the file.
You can register an atexit() handler to delete the file, but this will not necessarily be completely reliable, particularly if the program crashes.
If you want proper file locking, consider using flock(), although, it is cooperative.
I am developing an application in .NET Compact Framework 3.5, for Windows CE 6. I need to automate some data synchronization between the mobile application and a PC. So what I do is that, in the .NETCF application, I have a while loop that checks every few seconds, using System.IO.File.Exists(fullFilePath), whether the file I am expecting has been copied from the PC to the mobile device, through an ActiveSync connection.
Once the mobile app finds the file, it will open and read it using a StreamReader.
My problem is that, some times, File.Exists(fullFilePath) would return true, yet the subsequent use of StreamReader may fail with a FileNotFoundException.
Ruling out the possibility of the file getting deleted between the call to File.Exists() and the instantiation of the StreamReader, would anybody know how the exception may occur? Is it because file copy through ActiveSync is not atomic, such that the file is not actually ready for reading even though File.Exists() returns true?
A file copy is most certainly not going to be atomic. When you start the copy, the file is created, but has no data in it. As the file data gets written, the file "exists", but is not yet fully complete. You'd want to know not only that it exists, but that it's not currently in use (meaning the writer is done). Trying to open it exclusively would verify that.
I am trying to watch files in a directory to determine when files are opened/accessed. I thought FileSystemWatcher would do the trick using the event Changed.
Problem is that some applications do not create a lock on the file they open/access or change either the date modified or date accessed (even after fsutil behavior set disablelastaccess 0). Notepad for example. Apparently is makes a copy of the file in memory and plays with it there until you save it. Nor does it update the Date Accessed.
How can I monitor a directory of files and be notified when a file is simply opened/accessed by any program (e.g. Notepad)? Files may be opened from another computer, not necessarily on the computer running the "watcher".
I found lots of similar questions but did not see one focusing on file "access".
This is quite normal. Updating an existing file is quite dangerous since it can cause irretrievable data loss. A disk error (like disk full) while writing is very bad news. The common algorithm used:
rename the original file
write a new file using the original name
no error: delete the renamed file
error: delete the new file, rename original file back
Clearly this doesn't cause a Changed event to be raised, no file was changed.
Sorry, I didn't read the question well enough. There is no notification whatsoever for an app just opening a file for reading. FSW can only detect changes to the file system. There is no ready alternative either, this requires a custom file system filter driver that snoops on driver requests. Like the kind that SysInternals' ProcMon utility uses. I'm not aware of such a driver ready for use in a C# program, you can't write them in C# either. This just isn't a common requirement.