Imports System
Imports System.Timers

Public Class Timer1
    
    Public Shared Sub Main()
        ' Normally, the timer is declared at the class level, so
        ' that it doesn't go out of scope when the method ends.
        ' In this example, the timer is needed only while Main 
        ' is executing. However, KeepAlive must be used at the
        ' end of Main, to prevent the JIT compiler from allowing 
        ' aggressive garbage collection to occur before Main 
        ' ends.
        Dim aTimer As New System.Timers.Timer()

        ' Hook up the Elapsed event for the timer.
        AddHandler aTimer.Elapsed, AddressOf OnTimedEvent

        ' Set the Interval to 2 seconds (2000 milliseconds).
        aTimer.Interval = 2000
        aTimer.Enabled = True
        
        Console.WriteLine("Press the Enter key to exit the program.")
        Console.ReadLine()

        ' Keep the timer alive until the end of Main.
        GC.KeepAlive(aTimer)
    End Sub
        
    ' Specify what you want to happen when the Elapsed event is 
    ' raised.
    Private Shared Sub OnTimedEvent(source As Object, e As ElapsedEventArgs)
        Console.WriteLine("Hello World!")
    End Sub
End Class

using System;
using System.Timers;

public class Timer1
{
    public static void Main()
    {
        // Normally, the timer is declared at the class level, so
        // that it doesn't go out of scope when the method ends.
        // In this example, the timer is needed only while Main 
        // is executing. However, KeepAlive must be used at the
        // end of Main, to prevent the JIT compiler from allowing 
        // aggressive garbage collection to occur before Main 
        // ends.
        System.Timers.Timer aTimer = new System.Timers.Timer();

        // Hook up the Elapsed event for the timer.
        aTimer.Elapsed += new ElapsedEventHandler(OnTimedEvent);

        // Set the Interval to 2 seconds (2000 milliseconds).
        aTimer.Interval = 2000;
        aTimer.Enabled = true;
 
        Console.WriteLine("Press the Enter key to exit the program.");
        Console.ReadLine();

        // Keep the timer alive until the end of Main.
        GC.KeepAlive(aTimer);
    }
 
    // Specify what you want to happen when the Elapsed event is 
    // raised.
    private static void OnTimedEvent(object source, ElapsedEventArgs e)
    {
        Console.WriteLine("Hello World!");
    }
}
 

#using <system.dll>

using namespace System;
using namespace System::Timers;

public ref class Timer1
{
public:
   static void Demo()
   {
      // Normally, the timer is declared at the class level, so
      // that it doesn't go out of scope when the method ends.
      // In this example, the timer is needed only while Demo
      // is executing. However, KeepAlive must be used at the
      // end of Demo, to prevent the JIT compiler from allowing 
      // aggressive garbage collection to occur before Demo
      // ends.
      System::Timers::Timer^ aTimer = gcnew System::Timers::Timer;

      // Hook up the Elapsed event for the timer.
      aTimer->Elapsed += gcnew ElapsedEventHandler( Timer1::OnTimedEvent );
      
      // Set the Interval to 2 seconds (2000 milliseconds).
      aTimer->Interval = 2000;
      aTimer->Enabled = true;

      Console::WriteLine("Press the Enter key to exit the program.");
      Console::ReadLine();

      // Keep the timer alive until the end of the Demo method.
      GC::KeepAlive(aTimer);
   }


private:
   // Specify what you want to happen when the Elapsed event is 
   // raised.
   static void OnTimedEvent( Object^ /*source*/, ElapsedEventArgs^ /*e*/ )
   {
      Console::WriteLine( "Hello World!" );
   }

};

int main()
{
   Timer1::Demo();
}