SoFunction
Updated on 2025-03-03

C++ file monitoring FileSystemWatcher

The specific code is as follows:

#using <>
#include <iostream>

using namespace std;
using namespace System;
using namespace System::IO;
using namespace System::Security::Permissions;

public ref class Watcher
{
private:
  // Define the event handlers.
  static void OnChanged( Object^ /*source*/, FileSystemEventArgs^ e )
  {
   // Specify what is done when a file is changed, created, or deleted.
   Console::WriteLine( "File: {0} {1}", e->FullPath, e->ChangeType );
  }

  static void OnRenamed( Object^ /*source*/, RenamedEventArgs^ e )
  {
   // Specify what is done when a file is renamed.
   Console::WriteLine( "File: {0} renamed to {1}", e->OldFullPath, e->FullPath );
  }

public:
  [PermissionSet(SecurityAction::Demand, Name="FullTrust")]
  int static run()
  {
   //array<String^>^args = System::Environment::GetCommandLineArgs();
   //Create a FileSystemWatcher and set its properties.   FileSystemWatcher^ fsWatcher = gcnew FileSystemWatcher( );
   fsWatcher->Path = "C:\\files";

   /* Watch for changes in LastAccess and LastWrite times, and
     the renaming of files or directories. */
   fsWatcher->NotifyFilter = static_cast<NotifyFilters>(//The following properties of the listening file are added as required. Here I have added some commonly used properties.                NotifyFilters::LastAccess | //Date of the last time a file or folder was opened.                NotifyFilters::LastWrite | //Date of last write content to a file or folder                NotifyFilters::FileName | //file name                NotifyFilters::DirectoryName | //Directory name                NotifyFilters::Size); //size
   // Listen to subdirectory   fsWatcher->IncludeSubdirectories = true;
   // Only watch text files.
   //fsWatcher->Filter = "*.txt";

   // Add event handlers.
   fsWatcher->Changed += gcnew FileSystemEventHandler( Watcher::OnChanged );
   fsWatcher->Created += gcnew FileSystemEventHandler( Watcher::OnChanged );
   fsWatcher->Deleted += gcnew FileSystemEventHandler( Watcher::OnChanged );
   fsWatcher->Renamed += gcnew RenamedEventHandler( Watcher::OnRenamed );

   // Begin watching.
   fsWatcher->EnableRaisingEvents = true;

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

   return 0;
  }
};

int main() {
  Watcher::run();
}

Procedure 1. First create the FileSystemWatcher object to set some properties and add listening events

2. Set up the listening directory

3. Set the properties of the listening file

4. Set up the listening subdirectory

5. Add listening events

6. Start monitoring

The sample code above can be found on MSDN. If there is any uncertainty, you can check it out.document