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streamReader inside OnChanged fires twice?

Asked 3 days ago Modified today Viewed 177 times Asked By Satish Narayana Sagina

I have a small application that watches a specific file and whenever it changes, my application should do the actions in the loop, but something is firing the function more than once!! here's my code

private void OnChanged(object source, FileSystemEventArgs e)
{
    if (e.FullPath == @"C:\test.txt")
    {
        string textFilePath = @"C:\test.txt";

        try
        {
            using (var streamReader = File.OpenText(textFilePath))
            {
                var lines = streamReader.ReadToEnd().Split("\r\n".ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
                foreach (var line in lines)
                {
                    //actions here
                }
            }
        }
        catch (Exception)
        {
        }
    }
}

So I'm guessing in the loop when streamreader do File.OpenText somehow is firing the function again?! any ideas?

Answers

From MSDN:

The Changed event is raised when changes are made to the size, system attributes, last write time, last access time, ...

So yes, opening (actually: closing) the file will raise the Changed event again.

You can use the NotifyFilter to limit the actions your watcher triggers on.

Answered by Hemanth Kumar Vanakedi 3 days ago

SOLUTION So I did one small thing that controlled the issue, I added a counter and always check if it's not the first time, skip and reassign it to 0.

private int fireCounter = 0;

    private void OnChanged(object source, FileSystemEventArgs e)
    {
        fireCounter++;

        if (fireCounter == 1)
        {
            delete();

            if (e.FullPath == @"C:\test.txt")
            {
                Thread.Sleep(2000);
                //I added Sleep for two seconds because without it sometimes it wont work

                string textFilePath = @"C:\test.txt";
                try
                {
                    using (var streamReader = File.OpenText(textFilePath))
                    {
                        var lines = streamReader.ReadToEnd().Split("\r\n".ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
                        foreach (var line in lines)
                        {
                            //Actions Here
                        }
                    }
                }
                catch (Exception)
                {
                }
            }
        }
        else
        {
            fireCounter = 0;
        }
    }

Answered by naveen020 Kolluri 3 days ago