Question

Is there any possible way to access the field – str in the Class Program and the variable num – in the main function?

class Program
{
    string str = "This is a string";
    static void Main(string[] args)
    {
        int num = 100;
        Debug.WriteLine(Thread.CurrentThread.ManagedThreadId);
        var timer = new System.Timers.Timer(10000);
        timer.Elapsed += new ElapsedEventHandler(timer_Elapsed);
        timer.Start();
        for (int i = 0; i < 20; i++)
        {
            Debug.WriteLine(Thread.CurrentThread.ManagedThreadId + " " + "current I is " + i.ToString());
            Thread.Sleep(1000);
        }
        Console.ReadLine();
    }

    static void timer_Elapsed(object sender, ElapsedEventArgs e)
    {
        Debug.WriteLine(str);
        Debug.WriteLine(num);
        Debug.WriteLine(Thread.CurrentThread.ManagedThreadId + "  current is timer");
        //throw new NotImplementedException();
    }
}

Best Regards,

Answer 1

The field just needs to be made static.

static string str = "This is a string";

To access num you need to use a lambda expression.

timer.Elapsed += new ElapsedEventHandler((s, e) =>
{
     Debug.WriteLine(str);
     Debug.WriteLine(num);
     Debug.WriteLine(Thread.CurrentThread.ManagedThreadId + "  current is timer");

});

You can also use an anonymous method.

timer.Elapsed += new ElapsedEventHandler(delegate(object sender, ElapsedEventArgs e)
{
     Debug.WriteLine(str);
     Debug.WriteLine(num);
     Debug.WriteLine(Thread.CurrentThread.ManagedThreadId + "  current is timer");

});

There is one more option. The System.Threading.Timer class allows you to pass a state object.

var timer = new System.Threading.Timer((state) =>
{
     Debug.WriteLine(str);
     Debug.WriteLine(state);
     Debug.WriteLine(Thread.CurrentThread.ManagedThreadId + "  current is timer");
}, num, 10000, 10000);