How to end a loop waiting for while (Console.Read() != 'q' );

Question

_{Wednesday, April 6, 2011 7:58 PM}

I originally was trying to create a windows service (to watch for a file change (add) ) but was unable to do to company restirctions.? So i got the idea to start a console app with a scheduled task and just wait for the user to end it (while in testing)? Well, i am at the point where that part of testing is complete and now need to have the app stop itself after the onchange event fires one time here is the code:

[PermissionSet(SecurityAction.Demand, Name = "FullTrust")]
public static void Run()
{
 FileSystemWatcher watcher = new FileSystemWatcher();
    watcher.Path = @"C:\testWatcher\";
    watcher.NotifyFilter = NotifyFilters.LastAccess | NotifyFilters.LastWrite
            | NotifyFilters.FileName | NotifyFilters.DirectoryName;
    watcher.Filter = "*.xls*";
    watcher.Created += new FileSystemEventHandler(OnChanged);
    watcher.EnableRaisingEvents = true;

 // Wait for the user to quit the program.
    Console.WriteLine("Press \'q\' to quit the sample.");
    while (Console.Read() != 'q') ;
} 


private static void OnChanged(object source, FileSystemEventArgs e)
{
 try
    {
     ImportPVC.ProcessDailyTx();
 //After this fires once exit program

 }
    catch //(Exception ex)
    { }
}

All replies (5)

_{Wednesday, April 6, 2011 8:36 PM ✅Answered}

Console.Read() blocks the STAThread on which the console app is running.  The only thing that code will do is block until the user presses 'q'.

Enjoy: http://social.msdn.microsoft.com/forums/en-US/csharpgeneral/thread/5f954d01-dbaf-410a-9b0d-6bb6f57d0b85/

_{Wednesday, April 6, 2011 10:57 PM ✅Answered}

The following should work.  It will quit if the user hits Q or if the watcher.Created event gets fired.  Hopefully it makes sense to you but if not please let me know.

[PermissionSet(SecurityAction.Demand, Name = "FullTrust")]
public static void Run()
{
  bool Changed = false;
  using (FileSystemWatcher watcher = new FileSystemWatcher(@"C:\Users\", "*.xls"))
  {
    watcher.EnableRaisingEvents = true;
    watcher.NotifyFilter = NotifyFilters.LastAccess | NotifyFilters.LastWrite | NotifyFilters.FileName | NotifyFilters.DirectoryName;
    watcher.Created += delegate(object source, FileSystemEventArgs e)
    {
      // do whatever you want here...set Changed to true if you want the app to exit
      Changed = true;
    };

    Console.WriteLine("Press \'Q\' to quit the sample.");
    ConsoleKeyInfo cki;
    while (!Changed && (!Console.KeyAvailable || (cki = Console.ReadKey(true)).Key != ConsoleKey.Q))
    {
      Thread.Sleep(1);  // give up a timeslice to avoid 100% CPU usage while sleeping
    };
  }
}

HTH

ShaneB

_{Friday, April 8, 2011 9:06 AM ✅Answered | 1 vote}

Hi WIJ,

If you expect the application stop itself after the onchange event fires one time, you can call the exit method in the OnChanged method like this:

      private static void OnChanged(object source, FileSystemEventArgs e)

        {

            try

            {

                ImportPVC.ProcessDailyTx();

                Environment.Exit(0);

            }

            catch //(Exception ex)

            { }

        }

_{Wednesday, April 6, 2011 8:02 PM}

Doesn`t this code:

 Console.WriteLine("Press \'q\' to quit the sample.");
    while (Console.Read() != 'q') ;

do what you want?

It leaves the while loop when the user enters "q".

Wheres the problem?

Mitja

_{Tuesday, April 12, 2011 8:37 PM}

ConsoleKeyInfo cki;
cki = Console.ReadKey(true);

while (hidden.KeyChar != 'q')
{
 //do something...
 
 
 //and than wait for user input,,,
  cki = Console.ReadKey(true);
}

no need to treath.sleeping, this just wait for the user to press any key (and if key is q, quit!)

jeo suprima