Checking if my Windows application is running

Question

How do I check if my C  Windows application is running     I know that I can check the process name but the name can be changed if the exe changes   Is there any way to have a hash key or something to make my application unique

User · Answer

For my WPF application i ve defined global app id and use semaphore to handle it   public partial class App   Application             private const string AppId    c1d3cdb1-51ad-4c3a-bdb2-686f7dd10155          Passing name associates this sempahore system wide with this name     private readonly Semaphore instancesAllowed   new Semaphore 1  1  AppId        private bool WasRunning   set  get         private void OnExit object sender  ExitEventArgs e                  Decrement the count if app was running         if  this WasRunning                        this instancesAllowed Release                         private void OnStartup object sender  StartupEventArgs e                  See if application is already running on the system         if  this instancesAllowed WaitOne 1000                         new MainWindow   Show                this WasRunning   true              return                       Display         MessageBox Show  An instance is already running               Exit out otherwise         this Shutdown

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The recommended way is to use a Mutex  You can check out a sample here    http   www codeproject com KB cs singleinstance aspx  In specific the code                              check if given exe alread running or not                          returns true if already running         private static bool IsAlreadyRunning                         string strLoc   Assembly GetExecutingAssembly   Location              FileSystemInfo fileInfo   new FileInfo strLoc               string sExeName   fileInfo Name              bool bCreatedNew               Mutex mutex   new Mutex true   Global    sExeName  out bCreatedNew               if  bCreatedNew                  mutex ReleaseMutex                 return  bCreatedNew

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Checkout  What is a good pattern for using a Global Mutex in C       unique id for global mutex - Global prefix means it is global to the machine const string mutex id    Global   B1E7934A-F688-417f-8FCB-65C3985E9E27     static void Main string   args        using  var mutex   new Mutex false  mutex id                    edited by Jeremy Wiebe to add example of setting up security for multi-user usage            edited by  Marc  to work also on localized systems  don t use just  Everyone            var allowEveryoneRule   new MutexAccessRule new SecurityIdentifier WellKnownSidType WorldSid  null   MutexRights FullControl  AccessControlType Allow           var securitySettings   new MutexSecurity            securitySettings AddAccessRule allowEveryoneRule           mutex SetAccessControl securitySettings              edited by acidzombie24         var hasHandle   false          try                       try                                  note  you may want to time out here instead of waiting forever                   edited by acidzombie24                   mutex WaitOne Timeout Infinite  false                   hasHandle   mutex WaitOne 5000  false                   if  hasHandle    false  return   another instance exist                           catch  AbandonedMutexException                                   Log the fact the mutex was abandoned in another process  it will still get aquired                               Perform your work here                    finally                         edit by acidzombie24  added if statemnet             if  hasHandle                  mutex ReleaseMutex

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you need a way to say that  i am running  from the app    1  open a WCF ping service  2  write to registry file on startup and delete on shutdown 3  create a Mutex       i prefer the WCF part because you may not clean up file registry correctly and Mutex seems to have its own issues

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public partial class App   System Windows Application       public bool IsProcessOpen string name                foreach  Process clsProcess in Process GetProcesses                           if  clsProcess ProcessName Contains name                                 return true                                   return false             protected override void OnStartup StartupEventArgs e                   Get Reference to the current Process         Process thisProc   Process GetCurrentProcess             if  IsProcessOpen  name of application exe      false                          System Windows MessageBox Show  Application not open                   System Windows Application Current Shutdown                      else                          Check how many total processes have the same name as the current one             if  Process GetProcessesByName thisProc ProcessName  Length  gt  1                                   If ther is more than one  than it is already running                  System Windows MessageBox Show  Application is already running                     System Windows Application Current Shutdown                    return                             base OnStartup e

User · Answer

I really simplistic way I guess would be  for every exe that is running  you could create open a file on disk in a known location  c  temp  with a special name  yourapp lock  and then just count how many of those there are   A harder way  would be to open up some inter-process communication  or sockets  so with the process list you could interrogate each process to see if it was your application

User · Answer

Enter a guid in your assembly data  Add this guid to the registry  Enter a reg key where the application read it s own name and add the name as value there   The other task watcher read the reg key and knows the app name

User · Answer

Mutex and Semaphore didn t work in my case  I tried them as suggested  but it didn t do the trick in the application I developed   The answer abramlimpin provided worked for me  after I made a slight modification   This is how I got it working finally  First  I created some helper functions    public static class Ext      private static string AssemblyFileName this Assembly myAssembly                string strLoc   myAssembly Location          FileSystemInfo fileInfo   new FileInfo strLoc           string sExeName   fileInfo Name          return sExeName             private static int HowManyTimesIsProcessRunning string name                int count   0          name   name ToLowerInvariant   Trim   Replace   exe                foreach  Process clsProcess in Process GetProcesses                          var processName   clsProcess ProcessName ToLowerInvariant   Trim                   System Diagnostics Debug WriteLine processName               if  processName Contains name                                 count                                      return count             public static int HowManyTimesIsAssemblyRunning this Assembly myAssembly                var fileName   AssemblyFileName myAssembly           return HowManyTimesIsProcessRunning fileName             Then  I added the following to the main method    STAThread  static void Main         const string appName    Name of your app           Check number of instances running         If more than 1 instance  cancel this one         Additionally  if it is the 2nd invocation  show a message and exit      var numberOfAppInstances   Assembly GetExecutingAssembly   HowManyTimesIsAssemblyRunning        if  numberOfAppInstances    2               MessageBox Show  The application is already running             nClick OK to close this dialog  then switch to the application by using WIN   TAB keys            appName  MessageBoxButtons OK  MessageBoxIcon Warning              if  numberOfAppInstances  gt   2                return             If you invoke the application a 3rd  4th     time  it does not show the warning any more and just exits immediately

User · Answer

you can simply use varialbles and one file to check for running your program   when open the file contain a value and when program closes changes this value to another one

[c#] Checking if my Windows application is running

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