weird problem with String.IsNullOrEmpty

Question

User65893105 posted

I have some code that checks a string for null or empty but its not working correctly

if (string.IsNullOrEmpty(serializedValue))
            {
                throw new ArgumentNullException("serializedValue",
                                                string.Format("Parsing {0} : parameter cannot be empty or null",
                                                              enumeratedType.Name));
            }

serializedValue does contain a value, but the code always moves into the exception, it should skip past it.  Im using .net 4.5, has anyone else experienced this ?  Is there a root cause and fix ?

Answer 1

User-760709272 posted

If it contained a value it wouldn't go into the exception.  Do you *know* it has a value as you have checked in the debugger?  Or are you assuming it has a value?

Answer 2

User1577371250 posted

I don't think it will go to Exception if it has a value.

Please check the following.

1. put a breakpoint for value  and check whether it has a value.

string value = serializedValue;

if (string.IsNullOrEmpty(serializedValue)) 
{
 throw new ArgumentNullException("serializedValue", string.Format("Parsing {0} : parameter cannot be empty or null", enumeratedType.Name));
}

Answer 3

User65893105 posted

ive stepped through it in the debugger, the variable does contain a value, strangely, even though it steps into the line, it doesn't actually raise the exception, then it steps into the correct branch of the code ! weird

Answer 4

User1577371250 posted

Can you show the few more lines of code?

Answer 5

User-760709272 posted

It looks to me that the process you are debugging doesn't match the code in your Visual Studio.

Answer 6

User1577371250 posted

Yes, As Aidyf said you might be in the cached version of the application.

Answer 7

User-484054684 posted

strangely, even though it steps into the line, it doesn't actually raise the exception, then it steps into the correct branch of the code ! weird

From this statement, I believe, you don't have equivalent catch block in this part and so, the control goes to the previous file (caller) and if you have a catch block in that layer - put a breakpoint in the catch block, and you may see the control hitting the catch block.

If there are multiple catch blocks in each layer and if you are unsure, I'd suggest to put breakpoints on each catch block and see.