Best way to achieve this?

Best way to achieve this?

• Douglas H. Troy

  You could use a loop and then use a break statement in the if part of the loop.
  
  
  

• dr.acv

  I gave it ago and ran into some problems.
  
  private void mainForm_Load(object sender, EventArgs e)
  {
  FileSystemWatcher watcher = new FileSystemWatcher();
  watcher.Path = Environment.GetEnvironmentVariable("SystemRoot")";
  watcher.NotifyFilter = NotifyFilters.LastAccess | NotifyFilters.LastWrite | NotifyFilters.FileName;
  watcher.Filter = "file.dat";
  watcher.IncludeSubdirectories = false;
  //watcher.InternalBufferSize = 32384;
  Console.Out.WriteLine(watcher.InternalBufferSize.ToString());
  
  watcher.Changed += new FileSystemEventHandler(OnChanged);
  watcher.Created += new FileSystemEventHandler(OnChanged);
  watcher.EnableRaisingEvents = true;
  }
  
  private static void OnChanged(object source, FileSystemEventArgs e)
  {
  Console.Out.WriteLine(e.FullPath.ToString());
  File.Delete(e.FullPath);
  }
  
  Problems:
  
  If the file exists when the program starts its not deleted (as its only detecting changes, simpile if file exists delete should fix it )
  If the file is found as soon as its created i get the error file is in use.
  
  

• wencey

  what/who exactly are you referring to xRuntime :-)
  
  

• bw12117

  take a look at this, more about the FSW class:

  http://msdn2.microsoft.com/en-us/library/system.io.filesystemwatcher.aspx

  Hopefully the examples provided will give you a clearer vision!

  edit: looks like Andrej also provided the link ;-)

   

  
  
  

• l Bllizzd l

  For the first question - yes, you could check if file exists when application starts.
  For the second one, look for Matthew's pointers a few posts up; you have to wait till file is released. If it's a large file, writing could take a bit longer.

  Andrej

  
  
  

• rWarrior

  Ok thanks for the replies, i thought when you return you exited the method.
  
  Ill have a look at the file watcher.
  
  Thanks all
  
  

• Phil Rogers

  Watch out though - if the file you want to delete is still in the process of being created when you attempt to delete it, an exception will be thrown.
  
  You'd have to:
  
  * In a loop, wait for the file to appear (or use FileSystemWatcher)
  * In a loop, keep trying to delete the file until it is deleted (or the loop has run a certain number of times, in which case an error should be returned or displayed).
  
  In both loops, you MUST put a short pause in (Sleep(200) or somesuch) otherwise you'll hammer the CPU/disk and the system will be sluggish.
  
  
  

• JRQ

  here is one way of doing it:

  while (!Check()) { Console.WriteLine("Checking..."); } this.Delete(); private static bool Check() { if (File.Exists(Environment.GetEnvironmentVariable("SystemRoot") + @"\myfile.dat")) { return true; } else { return false; } } public static void delete() { if (File.Exists(Environment.GetEnvironmentVariable("SystemRoot") + @"\myfile.dat")) { File.Delete(Environment.GetEnvironmentVariable("SystemRoot") + @"\myfile.dat"); Console.WriteLine("Deleted"); } }

  this could be a problem:

• constantly checking to see if a file exists, application would hang (the UI) if it were a WinForms app because if the file doesnt exist, you are constantly checking it until it does exist - this file may not exist until say, tomorrow so its ineffecient really

  What exactly are you trying to achieve or rather when I know you are checking for a file but why check it in a loop until it exists Perhaps there is another way we can help you if you can tell us more in depth about what you are trying to achieve