Input String was not in correct format in asp.net

Question

We've been facing an issue while saving our page. It throws "Input String was not in correct format". After trying so many time, we found there was no problem with the code, but with the "Cache (Temporary Internet File"). After Cache was cleared, it saved without any error. Does anyone knew the reason behind it?

Answer 1

That sounds like the sort of error that you get from a bad parse, say Int32.Parse("foo") where you were expecting "foo" to be something like "123" . I am not sure why this would be affected by the cache.

My recommendation would be to look at the method where the exception occurs and see if it attempts to parse a string. If you expect that the string might not be in the correct format (say, it's a string entered by the user, you can replace

int i = Int32.Parse(myString);

with

int i;
if (Int32.TryParse(myString, out i))

Then you can handle the case of bad input in the else .

If however you expect the string should always be in the correct format (in other words, this is truly "exceptional" behavior), then I would leave it as a Parse and add a catch (FormatException ex) , and within the catch log the string that caused the exception. This should hopefully help you in tracking down the underlying cause of the problem.

Or if the problem has never reoccured since you cleared the cache back in October of '09, just chalk it up to cosmic rays and move on I guess. ;)