Question

Possible Duplicate:
Why catch and rethrow Exception in C#?

I sometimes come across C# code that looks like this:

        try
        {
            // Some stuff
        }
        catch (Exception e)
        {
            throw e;
        }

I understand its possible to do something like log the exception message and then rethrow it. I’m talking about a catch that only rethrows the exception. I don’t see a point to this. I have three questions:

1) Is there any advantage to this

2) Does this slow doen the code at all

3) Would it make any difference if the catch block were as follows:

        catch (Exception)
        {
            throw;
        }

Answer 1

This rethrows the exact same exception:

    catch (Exception)
    {
        throw;
    }

Whereas this rethrows the exception without the original stack trace:

    catch (Exception e)
    {
        throw e;
    }

There is often a good reason for throw; as you can log the exception or do other things prior to rethrowing the exception. I am not aware of any good reasons for throw e; as you will wipe out the valuable stack trace information.