using System;

public class Program

{

    public static void Main()

    {

        ExceptionTesting et = new ExceptionTesting();

        Console.WriteLine("Bad exception handling example, throws 'ex' rather than just throwing.  In this case we lose some of the stack trace");

        try

        {

            et.CatchExceptionThenThrowEx();

        }

        catch (Exception ex)

        {

            Console.WriteLine(ex.Message);

            Console.WriteLine(ex.StackTrace);

        }

        Console.WriteLine("Note how in the above stacktrace, it looks like the exception originated from CatchExceptionThenThrowEx, where it actually originated several function calls deeper.");

        Console.WriteLine("\n\n");

        Console.WriteLine("Good exception handling example, throws when an exception occurs.  In this case we keep the entirety of the stack trace");

        try

        {

            et.CatchExceptionThenThrow();

        }

        catch (Exception ex)

        {

            Console.WriteLine(ex.Message);

            Console.WriteLine(ex.StackTrace);

        }

        Console.WriteLine("Note how in the above stacktrace, we can see that the exception actually originaed in FinishTHings.");

    }

}

​

public class ExceptionTesting

{

    public void CatchExceptionThenThrow()

    {

        try

        {

            StartThings();

        }

        catch (Exception)

        {

            throw;

        }

    }

    public void CatchExceptionThenThrowEx()

    {

        try

        {

            StartThings();

        }

        catch (Exception ex)

        {

            throw ex;

        }

    }

    private void StartThings() 

    {

        this.ProcessingThings();

    }

    private void ProcessingThings()

    {

        this.FinishThings();

    }

    private void FinishThings()

    {

        throw new Exception("Throw that exception");

    }

}