Noftiy that file is deleted

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C#

How can I notify the user when the currently active file is deleted from the saved location.

Thank you!

Posted 5-Dec-10 21:00pm

subhash04573

Updated 5-Dec-10 21:07pm

Manfred Rudolf Bihy

v2

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Toli Cuturicu 6-Dec-10 3:25am

"the currently active file"... There is no such thing!

Manfred Rudolf Bihy 6-Dec-10 5:13am

@Toli: OP is most likely looking at this from the perspective of his application scenario, but to reduce the confusion he should have elaborated on what he means by "currently active file". Or maybe not use the phrase altogether, since it doesn't add any information whatsoever. :)

Manfred Rudolf Bihy 8-Dec-10 7:37am

Did place that one vote? I hope not as I did answer your question correctly and even had a solution for your follow up question.

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Manfred Rudolf Bihy · Answer 1 · 2010-12-05T21:06:00

Solution 1

Hi Subhash,

I'm not quite sure what you mean by "currently active file", but if you want to get notified of file changes, renames, moves and deletions on way to go is to use the FileSystemWatcher class. It lets you handle all these kind of events.

Example:

C#

class Program
{
    private static FileSystemWatcher fw;
    static void Main(string[] args)
    {
        String path = args[0];
        String filter = args[1];

        fw = new FileSystemWatcher(path, filter);
        fw.Deleted += new FileSystemEventHandler(fw_Deleted);

        fw.NotifyFilter = NotifyFilters.Attributes | NotifyFilters.CreationTime |
                          NotifyFilters.DirectoryName | NotifyFilters.FileName |
                          NotifyFilters.LastAccess | NotifyFilters.LastWrite |
                          NotifyFilters.Security | NotifyFilters.Size;
        fw.IncludeSubdirectories = true;
        fw.EnableRaisingEvents = true;
        Console.ReadLine();
    }

    static void fw_Deleted(object sender, FileSystemEventArgs e)
    {
        Console.WriteLine("{3:yyyy-MM-ddTHH:mm:ss.ffff} Deleted event: {0} {1} {2}", e.Name, e.FullPath, e.ChangeType, DateTime.Now);
    }
}

This console application takes two command line parameters:
1. the path to watch e.g. c:\temp
2. which file extentions e.g. *.txt

Cheers

Manfred

Posted 5-Dec-10 21:06pm

Manfred Rudolf Bihy

Updated 5-Dec-10 21:12pm

v3

Comments

subhash04573 6-Dec-10 4:43am

i getting exception like path is not a legal form.
FileSystemWatcher watcher = new FileSystemWatcher();
watcher.Path = Path.GetDirectoryName(@"D:\");
watcher.Filter = Path.GetFileName(@"D:\help2.xml");

My requirement is i am using this xml file in the application. if the user goes to the location & deletes this xml file means. it should notify that file is deleted.

Manfred Rudolf Bihy 6-Dec-10 4:48am

Please do it like this: FileSystemWatcher watcher = new FileSystemWatcher(@"D:\","help2.xml");
or like this:
FileSystemWatcher watcher = new FileSystemWatcher();
watcher.Path = @"D:\";
watcher.Filter = "help2.xml";

For a good explanation of the FileSystemWatcher class and its methods, properties and events and also some examples see the MSDN documentation

That should do it :)

subhash04573 6-Dec-10 5:15am

namespace ConsoleApplication1
{
class Program
{

static void Main(string[] args)
{
FileSystemWatcher watcher = new FileSystemWatcher();
Console.WriteLine("Started....");

//watcher.SynchronizingObject = this;

watcher.Path = Path.GetDirectoryName(@"D:\Samples");
watcher.Filter = Path.GetFileName(@"*.xml");
watcher.NotifyFilter = NotifyFilters.LastWrite | NotifyFilters.FileName | NotifyFilters.Size;

watcher.Deleted += new System.IO.FileSystemEventHandler(OnDelete);
watcher.EnableRaisingEvents = true;

Console.ReadLine();

}
public static void OnDelete(object source, FileSystemEventArgs e)
{
Console.WriteLine("File: {0} Deleted",e.FullPath);
}

}
}

it's not raising any event even after deleting file .

Manfred Rudolf Bihy 6-Dec-10 5:18am

Please read my last comment. I showed you there what to put into the Path and Filter properties. Read my comment and do as you were told!

subhash04573 6-Dec-10 6:02am

i got it now.
Another thing. Can't we restrict the user for not to delete that file when it is in use.

Manfred Rudolf Bihy 6-Dec-10 6:18am

Sure you can, open the file:
StreadReader sr = new StreamReader(File.Open(fileName));
as long as you need to lock the file keep sr open. To release the lock call sr.Close();
As long as you have an open handle on the file the user can't delete it.

Please vote if my answer helped you!

Manfred Rudolf Bihy 6-Dec-10 8:05am

Yor are asking the same question over and over again seriously????

http://www.codeproject.com/script/Answers/MemberPosts.aspx?tab=questions&mid=7598829

You must be very confused, or do you have a better excuse?

subhash04573 7-Dec-10 23:47pm

The thing is what ever u said streamReader is right.
But in our application we are loading the document when ever the required, so i am getting exception like can't access the file it was accessed by some one.
In this case it will not work. Only if we one instance then it will work.

So,i am eagerly waiting for another alternative.

Srry for asking same question repeatedly.

Manfred Rudolf Bihy 8-Dec-10 0:40am

Even with FileAccess.Read it is not possible to open the same file twice so I have one more suggestion:
Make the access to this file through a class following the singleton pattern, so there will be only one instance.
Inside this class you encapsule all the operations you need on this file. One of the operations is making sure the file is only opened once, second it is being kept open as long as you need to lock that specific file. All operations on this file will be executed through this singleton. Sorry man, that's the best I can come up with right now.
I hope that is a viable option for you :)

R. Erasmus · Answer 2 · 2010-12-06T23:14:00

Heya,

/*--[ Function ]-----------------------------------------------------------*/
/*
  Function Name   : FileExist
  Description     : This function checks whether the file specified
                    by txtFilePath exists and returns file status.

  Access Modifier : public
  Param           : -none-

  Retval          : bool   : true  - file exists
                           : false - no such file
*/
/*-------------------------------------------------------------------------*/
public bool FileExist(string txtFilePath)
{
  bool returnValue;
  FileInfo genericFileInfo = new FileInfo(txtFilePath);
  returnValue = genericFileInfo.Exists;
  return returnValue;
}

You can use this function as an addition to checking whether a file exitst (not deleted) or not(deleted).
Hope this was useful!
Please vote!

Regards,