using System;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("123".ToInt32());

    }

}

​

public static class StringExtensions

{

    public static int ToInt32(this string value)

    {

        int result;

        if (int.TryParse(value, out result))

        {

            return result;

        }

​

        return 0;

    }

} 

​