Best practices for catching and re-throwing .NET exceptions

c# .net exception-handling rethrow
Seibar picture Seibar · Aug 22, 2008 · Viewed 186.3k times · Source

What are the best practices to consider when catching exceptions and re-throwing them? I want to make sure that the Exception object's InnerException and stack trace are preserved. Is there a difference between the following code blocks in the way they handle this?

try
{
    //some code
}
catch (Exception ex)
{
    throw ex;
}

Vs:

try
{
    //some code
}
catch
{
    throw;
}

Answer

Darren Kopp picture Darren Kopp · Aug 22, 2008

The way to preserve the stack trace is through the use of the throw; This is valid as well

try {
  // something that bombs here
} catch (Exception ex)
{
    throw;
}

throw ex; is basically like throwing an exception from that point, so the stack trace would only go to where you are issuing the throw ex; statement.

Mike is also correct, assuming the exception allows you to pass an exception (which is recommended).

Karl Seguin has a great write up on exception handling in his foundations of programming e-book as well, which is a great read.

Edit: Working link to Foundations of Programming pdf. Just search the text for "exception".

Related questions

Catch multiple exceptions at once?

It is discouraged to simply catch System.Exception. Instead, only the "known" exceptions should be caught. Now, this sometimes leads to unneccessary repetitive code, for example: try { WebId = new Guid(queryString["web"]); } catch (FormatException) { WebId = Guid.Empty; } catch (OverflowException) { WebId = …

Read More
How using try catch for exception handling is best practice

while maintaining my colleague's code from even someone who claims to be a senior developer, I often see the following code: try { //do something } catch { //Do nothing } or sometimes they write logging information to log files like following try catch …

Read More
Is there a difference between "throw" and "throw ex"?

There are some posts that asks what the difference between those two are already. (why do I have to even mention this...) But my question is different in a way that I am calling "throw ex" in another error god-like …

Read More