Exception Catching

CSharp · Console

/Program.cs

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");
	}
}