Merge catch blocks with exactly the same code? [duplicate]

Question

I want to merge the catch blocks in the following code for code reuse reasons:

try
{
    DoSomeInputOutput();
}
catch (InvalidOperationException ex)
{
    HandleKnownException1(ex);
}
catch (InvalidDataException ex)
{
    HandleKnownException1(ex);
}
catch (ArgumentNullException ex)
{
    HandleKnownException1(ex);
}
catch (ArgumentOutOfRangeException ex)
{
    HandleKnownException2(ex);
}
catch (ArithmeticException ex)
{
    HandleKnownException2(ex);
}
catch (InvalidCastException ex)
{
    HandleKnownException2(ex);
}
catch (Exception ex)
{
    HandleUnknownException(ex);
}

to something like this:

try
{
    DoSomeInputOutput();
}
catch (InvalidOperationException ex)
catch (InvalidDataException ex)
catch (ArgumentNullException ex)
{
    HandleKnownException1(ex);
}
catch (ArgumentOutOfRangeException ex)
catch (ArithmeticException ex)
catch (InvalidCastException ex)
{
    HandleKnownException2(ex);
}
catch (Exception ex)
{
    HandleUnknownException(ex);
}

Is that possible somehow?

Thanks.

Answer 1

Presumably, you do it in more than one place. If so, why don't you do this:

{
    DoSomeInputOutput();
}
catch (Exception ex)
{
    HandleInputException(ex);
}

void HandleInputException(Exception ex)
{
   if (ex is InvalidOperationException || ex is InvalidDataException || ex is ArgumentNullException)
   {
     HandleKnownException1 (ex);
   }
   else if ...
   else if ...
}

Answer 2

No (or at least: not unless the exceptions you want to group happen to share a common base-class specific to that group, which they don't in your example); the only thing you can do in this scenario is catch (Exception ex) and do runtime testing on ex. By the time you've done that, I expect your code is already "prettier" as-is (since, importantly, you've already refactored the handling code into a method).

I'd be tempted to tweak the spacing so I can focus on the important code:

try
{
    DoSomeInputOutput();
}
// blah humorous scenario 1
catch (InvalidOperationException ex) { HandleKnownException1(ex); }
catch (InvalidDataException ex) { HandleKnownException1(ex); }
catch (ArgumentNullException ex) { HandleKnownException1(ex); }
// blah whimsical scenario 2
catch (ArgumentOutOfRangeException ex) { HandleKnownException2(ex); }
catch (ArithmeticException ex) { HandleKnownException2(ex); }
catch (InvalidCastException ex) { HandleKnownException2(ex); }
// unexpected comedy
catch (Exception ex) { HandleUnknownException(ex); }

(or something).

In some ways this also ties into this question: switch / pattern matching idea.